Reconstruction: On Luigi Nono’s A Pierre and Post-prae-ludium
Introduction
One of the problems inherent in the preservation and dissemination of live electronic music is the dependence of many such works on a specific set of tools. The use of apparatus created primarily for the recording and reproduction of sound (microphones and tape recorders) or for the measurement and testing of signals in the studio environment (tone and noise generators) is intertwined with the beginning of electroacoustic music. The transition from adapting these machines for creative purposes during the 1950s towards the construction of dedicated tools for electronic music creation during the 60s and 70s, as well as the advent and democratisation of computer technology during the 80s and 90s into the present, has created a flow of technological development, and therefore, of technological obsolescence. This has contributed to a difficulty in preserving musical works created with a specific technology in their original format, posing serious problems for the sustainable reproducibility of compositions involving live electronics, and therefore, for establishing a core repertoire to relate to as practitioners.
There are two main approaches to tackling this issue. The first approach advocates fidelity to the original conditions under and in which the piece was created, and defends and promotes the use of the original tools and technical setups.1 Although this would arguably be the ideal choice, particularly since the inherent limitations of certain tools are as obvious in the final result of a piece as are their declared features, the practicalities of such an approach negatively affect the potential of this music to be widely disseminated since it requires not only equipment that is difficult and costly to acquire and maintain but also a build-up of time and manpower that prohibits access to the setup for extended periods of time in contexts outside big, well-funded productions.
A second approach towards the preservation of live electronic music works is focused on dissemination and transferability. Starting with the acknowledgment that the replacement of certain components or tools in the original setup of a piece will undoubtedly transform the final sonic result, this approach chooses to design digital models (mainly in software) of the entire system required for the reproduction of a piece. Although this reduces the costs while increasing the possibility of dissemination, it generates a new set of problems: first, the inherent limits of the tools are lost (along with their impact in the decision making process of the composer while making the piece); second, there is a lack of standardised computer tools.
The paradox of replacing potentially obsolete technologies with current ones is that the notion of currency has become increasingly ephemeral, particularly in digital media. Anyone familiar with current consumer-oriented computer technology has suffered the pressure to accept a schedule of obsolescence that gets shorter and shorter. This means that – even when the software tools created and used by computer musicians attempt to remain stable and backwards-compatible – the operating systems of the platforms used to run these tools might have a completely different agenda.2
1 Such is the case in several of Steve Reich’s productions of pieces requiring AKAI samplers and their floppy-disk-loaded sound banks, and, more pertinently to this thesis, performances of music by Luigi Nono produced during his time at the
Experimentalstudio der Heinrich-Strobel-Stiftung des Südwestfunks in Freiburg.
2 The endless back-and-forth exchange between publishers and potential performers of pieces using digital live electronic elements has become an almost unavoidable part of the preparation process of a performance — a process that discourages many non-technically-oriented musicians from approaching this repertoire.
Context
In the 1980s, the last decade of his musical career, Luigi Nono felt the positive impact of technology on culture and its contribution to social emancipation. At the same time, his output departed from the directly political topics he raised in his earlier works and began exploring the creation of music that proposed new ways of listening. These explorations culminated in Prometeo (1984), featuring texts by Hesiod, Friedrich Hölderlin and Walter Benjamin, which explores the origin and evolution of humanity. Nono’s shift towards a timeless and visionary context, which questions and challenges the relationship of oneself with the environment through listening, is expressed in his beautiful 1983 text “L’errore come necessità” (Nono 2001: 522):
Silence.
Listening is very difficult.
Very difficult to listen to others in the silence.
Other thoughts, other noises, other sounds, other ideas. When one comes to listen, one often tries to rediscover oneself in others. To rediscover one’s own mechanisms, system, rationalism in the others.
And this is a violence of the utmost conservative nature.
Instead of hearing the silence, instead of hearing the others, one often hopes to hear oneself once again. That is an academic, conservative, and reactionary repetition. It is a wall against ideas, against what is not yet possible to explain today.
. . . To listen to music.
That is very difficult.
I think it is a rare phenomenon today.
. . .
Perhaps one can change the rituals; perhaps it is possible to try to wake up the ear. To wake up the ear, the eyes, human thinking, intelligence, the most exposed inwardness.
This is now what is crucial.3
Pianist and musicologist Paulo de Assis (2014: n.p.) remarks that
Nono’s late works bring the inner musical structures and features to the foreground, focusing on small instrumental forces, on subtle harmonic fields and clearly differentiable vertical sound-aggregates, on extreme soft dynamics and fine articulation markings, on fragmented successions of sections, and on a highly elaborated dialogue with old historical forms. The act of listening to these works becomes a highly demanding process – the listener being confronted with his/her own capacity of listening.
Works from Nono’s late period require a completely different attitude to the conception of the work as a whole: sound perception, flexibility in the notation, the behaviour of performers, and positioning musicians and audience in the concert space. Regarding this concert space, musicologist Angela De Benedictis remarks that it “was conceived as an environment in which spatial and temporal relationships could form part of a total dimension both in acoustic terms (with the multiplication and spatialization of the sound sources) and visually (by eliminating the separation of stage and auditorium).” (De Benedictis 2013: n.p.) The antecedents for this use of the space in Nono’s work come from the polychoral practice of the composers of the San Marco Basilica in Venice, such as Andrea and Giovanni Gabrieli and Adrian Willaert. (Raposo Martín 2009: 281)
Nono’s search for an ever-moving sound to activate the concrete and perceptual musical space he was proposing, what he calls the suono mobile, dates back to his Epitaffio No. 2 from 1952 – in other words, before starting to work with live electronics.4 “The execution of the same sound by different instruments situated on different points onstage, carries a stereophonic, spatial, group quality that conditions and modifies how the total sound effect that reaches the audience is heard.”5 (Raposo Martín 2009: 277)
In preparation for performances of his large later works involving electronics, such as Prometeo (1984), Caminantes…..Ayacucho (1986–1987) and No hay caminos, hay que caminar.....Andrej Tarkowskij (1989), the position of the performers was determined by a careful calculation of the resonance characteristics of the venue. As a result, the orchestral groups were placed in different parts of the performance space to achieve the desired spatial trajectories for the sound lines between instruments.
Since the function of the live electronics in these works was primarily to extend, expand and project the instrumental resonances onto the physical space, for every new performance a new adaptation of placement and programming of the electronics was required, and thus flexibility in musical notation was necessary, as well as a sensitive understanding of the performer who must react to the subtleties of micro-variations in pitch, dynamics and timbre. In relation to this, Claudio Abbado (1999: 4–5) remarks that
While it is true that the acoustics of a hall will influence the sound of any music, the works of Nono have to be actually recreated in every new hall. It was a profoundly moving experience to bring Gigi’s music to life together with young musicians [Gustav Mahler Youth Orchestra], to explore boundaries, to overcome limitations, to realise the challenges of the score in ever changing circumstances: in other words to find new ways to new music.
In this last creative period, Nono also challenged the nature of the performative unit created by interpreters and their instruments – whether traditional or electronics. Highly accomplished performers were required to display a kind of “static” virtuosity: utmost concentration and control of the most subtle changes in sound, while retaining the ability to interact with the rest of the group.
Nono’s considerations of the potential of live electronics helped create a new “musical space” in order to challenge both audience perception and the spatial conventions of the concert situation, as well as the instigation towards performers to challenge their relationship with their instruments. These are elements that not only influenced my work as a composer – as I will explain in the case study “On Multiple Paths” – but also prompted me to reflect upon and make decisions about the demands towards the reconstruction of the technology and the performance practice of the electronic setups for his A Pierre. Dell’azzurro silenzio, inquietum and Post-prae-ludium nr. 1 per Donau.
3 Translation by Paulo de Assis.
4 Luigi Nono introduces the term suono mobile in his handwritten notes for Guai ai gelidi mostri (1983). (Nono 2001: 491-492)
5 My translation.
Project
I have been fortunate to work on Luigi Nono’s music in different capacities. My most striking experience was as a technical and artistic collaborator on the project “Seizing the Ephemeral”, led by musicologist Friedemann Sallis of the University of Calgary and conducted at the Banff Centre for the Arts in February 2009. This musicological, technical, and artistic research project aimed to unravel the musical secrets of A Pierre. Dell’azzurro silenzio, inquietum (1985), for contrabass clarinet in B♭and contrabass flute in G, and Post-prae-ludium nr. 1 per Donau (1987), for tuba and live electronics, to “capture, for conservation, transmission and study, those aspects of Nono’s late work that can not [sic] be notated conventionally.” (Burleigh and Sallis 2008: 1)
From now on, when mentioning this works, I will use the abbreviations A Pierre and Post-prae-ludium, respectively.
According to Sallis (Burleigh and Sallis 2008: 1),
A Pierre and Post-prae-Ludium involve real-time manipulation of sound, producing micro-tonal variation and spatial distribution of sounds and [...] these aspects have the effect of short-circuiting traditional musicological analysis. The musical scores provide reliable information for the preparation of a performance, however, as the editors admit “the acoustic and dynamic result [of a concert performance] will not correspond to the graphic notation.”
Since the graphic notation used to represent the actions of the live electronic component did not correspond with the sound result of the piece, it was necessary to look into the actual sound results to understand better the musical structure.
The method of the “Seizing the Ephemeral” project was, first, to produce a recording of both pieces, and, at a later stage, to analyse, study and interpret the recording by incorporating sonograms and other computer-based analyses into the traditional study of the score. In addition to the recording, the research data included interviews with the performers at the different stages of the project (preparation, rehearsal, concert and recording).
Initially, my involvement in this project was purely technical. The task was to create computer models of the original live electronics setup, to allow the performers and researchers involved uninterrupted access to the whole musical system for an extended period.
One of the drawbacks with creating digital versions of early electronic music setups are the choices that occur in the mapping and design of the interface. Unless one is using commercial software and adapting the signal processing and routing to the features and limitations of that software, the decisions made in rendering the functionality and signal flow will almost inevitably make the designer the most suitable performer of the system.
For this reason I was invited to become more involved in the project as a performer, thus expanding my own artistic involvement with the pieces through searching for connections between the score and the intrinsic potential of the electronic components of the two pieces. What is presented as notation for the electronic performer in the scores is more a suggested guideline for actions based on previous performances, rather than the product of a preconceived musical idea devised by Nono. I considered that by unravelling the potential interpretative opportunities available in the relationship between traditional instruments and electronic systems, I could both find my own artistic position and help to define what an electronic performer could contribute to these works.
I will now describe the electronic setups for both pieces, how I reconstructed them in the digital domain, what musical salients I identified in the reconstruction process and how they influenced my artistic choices.
A Pierre
The electronic setup consists of two delay lines set to no feedback, which results in a single repetition of any incoming signal. The delay times are twelve seconds for the first delay, and twenty-four for the second (which is effectively another twelve-second delay on top of the first). Anything played is thus repeated twice: first twelve and then twenty-four seconds later. The choice of these durations is far from arbitrary: they are the result of studio experiments conducted by Nono in collaboration with Hans Peter Haller at the Experimentalstudio der Heinrich-Strobel-Stiftung des Südwestfunks in Freiburg, whose goal was to find the threshold of short-term auditory memory. This twenty-four-second threshold emerged as the necessary time span to perceive a repeated sound event as new and thus no longer connected to its source. Further experiments targeted shortening this time span. Nono and Haller observed that if the repeated event was presented with an alteration in its timbre (filtered), the time span between original sound and repetition could be shortened by half: a filtered repeated event was perceived as new after only twelve seconds.6
This constitutes the entire electronic setup for A Pierre: an initial sound event is filtered and presented twelve seconds later, and presented again, unaltered, twenty-four seconds after its original exposition. The live electronic performer must make musical sense of this reality to help shape the structure of the piece.
A Pierre: Examples of the original score (fig. 1), original electronic setup diagram (fig. 2), my digital adaptation in the Max/MSP environment (fig. 3) and video of the controller used for the performance.
6 This kind of experimental setup is very interesting since it merges a psychoacoustic enquiry with an artistic one. Most research done on auditory time spans focus on either echoic memory (short-term span) and its connection to memory development and speech. (Anderson 1939: 95) Connecting these lines of research directly into the creative experimental process is what makes Nono so fascinating.
If the electronic performer were to stop analysing the piece once the technical setup was successfully reproduced, there would be little else for him or her to do other than to control the potential feedback from the microphones once they start picking up repeated information coming from the loudspeakers, and to balance the overall dynamics of the amplified instruments and the delayed signals. Were this the only job at hand, it would be easy to feel disappointment that there was not more to access – and therefore, influence – in the musical development of the piece.
My personal approach to the role of the electronic performer in A Pierre was to study the instrumental score to understand the challenges Nono set for the instrumentalists, and from there to consider how I could relate the electronic system to those challenges. In doing so I found a performance strategy informed by the material itself and not only based on aesthetic choices made by previous performers.
What I discovered was a deceptive simplicity. The score of A Pierre is written in 4/4 and has a tempo marking of ♩= 30. At first glance, there are very few events per bar (if we want to use note density as a measure). But precisely herein lies the stimulating aspect of this piece: the apparently simple tasks required from the performers become extremely complicated because of two factors.
The first factor – what I referred to above as the challenge of the performative unit – is to place performers in conflict with their instruments by demanding actions and sounds that go against their nature. Nono’s choice of dynamics and pitch make this true for both the flautist and the clarinettist. For most of the piece, the performers are asked to play at the top of their instrument’s pitch range but with extremely soft dynamics (pppp), which requires a high level of tension and gives very little control over the result – they play on the verge of breakdown. What this creates is only the first layer of confusion in this piece. It is extremely difficult for anyone playing, once the instruments are amplified and the sounds are being repeated in the space, to connect with certainty any actions with the sounding results.
The use of fermatas creates a second level of confusion for the performers. Their durations are up to the discretion of each performer, with suggested durations of six to eight seconds. These successfully destroy any sense of temporal stability in the otherwise rigid grid of 4/4 at ♩= 30.
So even if one performer wanted to stay in the grid, the other will have a six- to eight-second temporal suspension, which, added to the kind of sound material being produced, breaks any hope of metric stability. This confusion is already present before adding the layers of delayed instrumental sounds.
During my collaboration with the “Seizing the Ephemeral” project, I had the opportunity to reflect upon how these elements of the instrumental part of A Pierre influenced the setup of the electronic system and how they could potentially be reinforced by the performance of the electronic part. Given that the goal of the project was to shed light on the musical and structural elements of the piece that are absent in the score, I felt encouraged to introduce my take on Nono’s technical and creative choices into the performance as much as possible.
Although using digital technology to reproduce analogue electronic equipment, I attempted to preserve the inherent limitations of the automation and routing of the original setup, considering them part of the identity of the electronic instrument. In the case of A Pierre and Post-prae-ludium, these limitations of the original material are, more than technical considerations, connected to cost, dimensions and availability.
The use of dedicated hardware for each delay and filter necessitates a number of routing choices given the number of inputs and outputs and the processing power of the tools. The routing choices seem arbitrary when dealing with a computer-based version of the setup. It was, and still is, my opinion that these choices are not only an essential contributor to the sonic and structural identity of these pieces, but demand from the electronic performer decisions that lie between the technical and the artistic and, therefore, should be preserved when dealing with computer models.
I wanted to draw a connection between the apparent simplicity of the score and the unravelling complexity of the musical result. The challenge was to relate the task of keeping the balance between input and output levels for the electronic performer to the playing of very high pitches at very soft dynamics by the instrumentalists.
In the rehearsals conducted at the Banff Centre, with Marieke Franssen on contrabass flute and Carlos Noain Maura on contrabass clarinet, it became clearer that one of the biggest challenges was to control feedback in the system. This feedback was induced by two factors that were part of the original setup: The sound projection is done over four loudspeakers, two directly behind each performer and two at the back of the hall.
Since two microphones capture the sound of each performer and they sit directly in front of a loudspeaker, the amount of sound emanating from the loudspeaker that is recaptured by the microphone is quite substantial. To avoid immediate feedback, the electronic performer must constantly act as a real-time, human limiter-compressor who opens the microphones when the instruments are playing but reduces their sensitivity when the repetitions come back too loudly through the front speakers.
Accepting this task plunges the electronic performer into the twelve-seconds/twenty-four-seconds cycle of the piece and leads to more calculated choices for the sound location of the repetitions within the performance space.
Demo of the twelve- and twenty-four-second delay cycle, and the room feedback that needs to be controlled.
A Pierre. Dell'azzurro silenzio, inquietum
Marieke Franssen, contrabass flute, Carlos Noain, contrabass clarinet,
Juan Parra Cancino, live electronics.
The second source of feedback – an additional challenge for the electronic performer – comes from the use of band-pass filters to modify the first wave of repetitions. The schematics for the piece indicate that the incoming direct signal of each instrument’s microphone must be routed to the opposite speaker (so that the direct amplified sound of the flute comes from the speaker behind the clarinet and vice versa). In performance, this adds an extra layer of confusion, which makes controlling the feedback induced by the heavily filtered repetition entering the microphone (and going to the opposite front speaker) extremely difficult.
All these elements make the system very sensitive and fragile. The musical challenge that A Pierre poses to the electronic performer resides in controlling and balancing the overall sonic texture.7
7 Although some computer-based performances of this work take advantage of the automatisation and dynamic limiting and compression possibilities of today’s sound amplification technology, I strongly advocate preserving the risks of the original setup as the starting point for the creative contribution of the electronic performer in a concert situation.
Marieke Franssen, Tjeerd Oostendorp and Juan Parra Cancino during rehearsals at the Banff Centre, February 2009.
Haller (Haller 1999: 13) mentions that
Nono thought of the interpreter as an equal partner in his work. He considered the instrument and its player, a voice and the personality of the singer, as a unity. In his imagination an abstract sound could exist, but usually he connected it with the personality of an interpreter. [...] The flautist Roberto Fabbriciani played with his mouth and nose very close to the microphone; as a result of this experiment, the musician was able to additionally produce wind sounds with his breath directly in the microphone while he played a normal sound. [...] This playing technique represented one of the materials which Nono used for the flute part of Das atmende Klarsein, electronics sound extensions by means only of the microphone.
Although these timbral transformations might seem rudimentary compared to the possibilities of manipulation of timbre in electroacoustic music today, it is fair to say that no fundamental evolution has taken place in the world of signal processing in the digital domain since then.
Post-prae-ludium was studied, performed, and recorded during the “Seizing the Ephemeral” project, with tubist Tjeerd Oostendorp. In this piece, the main challenge for me was to adapt the original electronic setup, conceived for two electronic technicians, into a system controlled by one single performer, while preserving the limitations of both the original system and the tasks assigned to each technician.
Rather than using automatisation procedures in the digital domain, I opted for a simplified layout of the entire system interface where, emulating a rack of hardware equipment, I had all effects available and active at all times, and could activate any of the sections at all times, rather than shifting between each module or “programme”. In doing so, I succeeded in preserving the challenge of gatekeeping the incoming signal of the tuba, while being able to follow the path delineated during the performance and activate/deactivate each section of the electronic setup accordingly.
Post-prae-ludium
The creative process for Post-prae-ludium was somewhat similar to the one of A Pierre. Intended as the first of a series of pieces for solo instruments and live electronics written by Nono for (and with) his close collaborators, it ended up being the only one of these works ever officially finished.
Created in collaboration with tubist Giancarlo Schiaffini, the piece employed an experimentation process that started with the documentation of the extremes of the frequency and amplitude ranges of the tuba. Schiaffini remembers being asked to present his personal range extremes on the tuba, as well as his own approaches to timbre transformation. All these findings were then used as source material, organised on a score with a timeline, which provides a “traditional” linear progression to the time structure of the piece. Schiaffini recalls that “we experimented with different instrumental and live-electronics techniques. Sometimes it was a kind of improv to be recorded and studied.” (Tignor 2009: 9)
In addition, to adapt the sound to the musician, Nono was known to explore the instrumentalist’s sound world within experimental sessions such as this. Schiaffini states that “the composition was tailored to my technical possibilities; he wanted to know different transformation of sound (1st page), then the highest and the deepest pitch, the most powerful (loudest) and on these extremes (as fffff and ppppppp) he built the composition”. (Tignor 2009: 9)
Just like the apparent rigidity of the notation grid of A Pierre, Post-prae-ludium proposes a path to the performer where the first step of the journey seems to dissolve the apparent rigidity of the path itself. The piece is divided into five sections for the tubist and four programmes for the electronics, each of which are assigned to one of the sections of the piece. Extremes of pitch and the timbral limits of the tuba are explored in the instrumental part and are further shaped and expanded by a series of spatial and temporal displacements controlled by the electronic performer.
Post-prae-ludium per Donau: Examples of the original score (fig. 1), original electronic setup diagram (fig. 2) and my digital adaptation in the Max/MSP environment (fig. 3).
Originally, this piece required two technicians for the opening section. In this section the electronic setting consists of four delays of fixed duration (five, seven, ten and thirteen seconds of time difference) feeding into a double spatial rotation system developed by Hans-Peter Haller (and therefore named the Halaphon). The function of the first technician was actively to open and close the input of the tuba signal routed to the different delays, while the second one varied the speed of the Halaphons, which rotated in opposite directions (clockwise and counterclockwise). This produced an unpredictable layer of delayed and chopped-up tuba sounds that appeared unexpectedly from the speakers located in each corner of the room.
The score shows how the tuba player needs to switch from system to system, selecting the musical material offered, which depends on the path chosen. The score also presents a suggested dramaturgy for the opening and closing of the delay inputs that, given the different speeds of the halaphone and the choice of material produced by the tubist, inevitably creates different sound results from one performance to another.
Reflection
A close examination of the tools Nono used in his pieces with live electronics reveals how he was able to devise performative strategies that transcended the limitations and characteristics of the time and place in which these tools were created. His timeless, and therefore very current, musical notions are instrumental to my understanding of musicianship in live computer music. They can be distilled into two key concepts, which I will elaborate later: the transformation of the physical space over time and the challenge of the performative unit.
In addition, in the case of A Pierre, as in most of Nono’s pieces for multiple instruments and live electronics, there is the goal of con-fusion, understood as “fuse-with”. This is a task given to the traditional instruments, the aim being to create a common timbre by weakening the upper harmonics of the instrument (therefore generating a signal as close as possible to a sine-tone). The demand on the electronic performer is to deal with the delicate challenge of amplifying this con-fusion without adding any extra colour to the global spatial mix. For this reason, the use of compressors or limiters for the incoming signal is not recommended, since they might introduce a slight colouring that could potentially destroy the illusion of fusing the timbre of the two instruments.8
As a composer, I wanted to extract this information and reshape it in my own musical output using the experiences gained in the reconstruction of the tools and performance strategies of these two works by Nono. This was the initial impulse for the series of experiments leading to Multiple Paths (omaggio a Nono). As a performer, in order to transition from technical translation into performative analysis and decision-making, I sought to find points of connection between the inherent qualities of the original electronic setup and the instrumental score. The multithreaded role of the computer music practitioner reveals itself in this project, unfolding the creative and performative demands of a task that was meant to be purely technical: to create a digital version of the original electronic setup. This is what I call interpretation as reconstruction.
8 These ideas about con-fusion, as well as the technical and aesthetic functions of using very weak instrumental sounds, come from my personal notes taken both during the course on interpreting Luigi Nono's, conducted by André Richard (et al.) at the Fondazione Giorgo Cini, Venice, Italy, 2–7 November 2007, and during the performance and recording sessions of A Pierre. Dell'azzurro silenzio, inquietum and Post-prae-ludium nr.1 per Donau, organised by Friedemann Sallis at the Banff Centre for the Arts, 20–27 February 2009.
References
Abbado, Claudio (1999). “My Silent Friend: Remembering Luigi Nono.” Contemporary Music Review 18/1: 3–5.
Anderson, Virgil A. (1939). “Auditory Memory Span as Tested by Speech Sounds.” The American Journal of Psychology 52/1: 95–99.
Assis, Paulo de (2014). “Con Luigi Nono: Unfolding Waves.” Journal of Artistic Research 6. Retrieved 2 November 2014, from
http://www.researchcatalogue.net/view/51263/51264.
Burleigh, Ian and Friedemann Sallis (2008). “Seizing the Ephemeral: Recording Luigi Nono’s A Pierre Dell’azzurro silenzio, inquietum, a più cori and Post-Prae-Ludium per Donau at the Banff Centre.” Paper presented at the EMS Conference, Paris.
De Benedictis, Angela Ida (2013). “Biografia: Nono, Luigi” (trans. Mark Weir). Fondazione Archivio Luigi Nono ONLUS. Retrieved 2 November 2014, from http://luiginono.it/en/luigi-nono/biography
Haller, Hans Peter (2009). “Nono in the Studio – Nono in Concert – Nono and the Interpreters.” Contemporary Music Review 18/2: 11–18.
Nono, Luigi (2001). Scritti e colloqui. Ed. Angela Ida de Benedictis and Veniero Rizzardi. 2 vols. Lucca: Ricordi/LIM.
Raposo Martín, Juan José (2009). Luigi Nono: Epitafios Lorquianos: Estudio musiológico y analítico. Huelva, Spain: Hergué Editorial.
Tignor, Scott E. (2009). “A Performance Guide to Luigi Nono’s Post-prae-ludium no. 1 per Donau” (Doctoral dissertation). Denton: University of North Texas.