The following are recommended / have been useful in pursuing this topic:

N.B. This is as yet a very incomplete list and rather out-of-date--see bibliographies of my various articles for further titles
Books / articles / web articles:

Bret Battey - An Investigation into the Relationship between Language, Gesture and Music (web)
Wallace Berry - Structural Functions of Music
Michel Chion - Guide des objets sonores (1983)
Manfred Clynes - Microstructural Musical Linguistics (1995)
Pierre Couprie - Three analysis models for L'oiseau moqueur (1999)
Simon Emmerson - The Language of Electroacoustic Music ( 1986)
Robert Erickson - Sound Structure in Music
Brian Ferneyhough - Form-Figure-Style; The Tactility of Time; Il Tempo Della Figura
Rolf Inge Godøy - Knowledge in music theory by shapes of musical objects and sound-producing actions

Leigh Landy - Reviewing the musicology of electroacoustic music (and other writings)

Theo van Leeuwen - Speech, Music, Sound

Stephen McAdams - Spectral fusion and the creation of auditory images.
Andra McCartney - http://www.finearts.yorku.ca/andra/andra.html
Pierre Schaeffer - Traité des objets musicaux
Arnold Schoenberg - Fundamentals of Musical Composition
Denis Smalley - Spectro-Morphology and Structuring Processes; The Listening Imagination
Laurie Spiegel - contributions to twice list
Mark Sullivan - Performance of Gesture
Lasse Thoresen - Spectromorphology article

Barry Truax - Acoustic Communication
Trevor Wishart - On Sonic Art
Iannis Xenakis - Formalized Music

Composers:

Bacewicz, Grazyna
Bach, J.S.
Bach, C. P. E.
Bartok, Bela
Beethoven, Ludwig von
Bouhalassa, Ned
Cuellar,Carlos
Debussy, Claude
Dhomont, Francis

Diez, Consuelo
Falla, Manuel de
Gobeil, Gilles
Ligeti, Gyorgy
Liljeholm, Thomas
Lutoslawski, Witold
Mendelssohn-Bartholdy, Felix
Messiaen, Olivier
Mossolov, Alexander
Mozetich, Marjan
Paganini, Nicolo
Scarlatti, Domenico
Schafer, R. Murray
Shostakovich, Dmitri
Soler, Josep
Southam, Ann
Winiarz, John
Varese, Edgard
Xenakis, Iannis

Conversations / e-mails / listserv discussions:

Thanks to the many people who encouraged me in the various stages of this project:  my students at the University of Aveiro, particularly those in the Seminario and the advanced analysis class; my colleagues at the University of Aveiro -- Nancy Harper, Tomas Henriques, Carlos Galaricha, Oscar Mealha; my composition students and the dance students at Concordia and various colleagues in the Faculty of Fine Arts, especially Kevin Austin, Mark Corwin, Silvy Panet-Raymond; faculty at the Music department of the University of Salford, especially Derek Scott and Mick Wilson; participants in the CMI-99 conference in Musical Imagery, and the organizers who allowed me to present my work there; Alexandra Hettergott, Bruno Repp and Jøran Rudi for their detailed replies and thoughtful comments; membersof the list-serv "cecdiscuss" for their comments and queries; the jury of the SMPC Toronto2000: Musical Intersections conference for accepting the proposal for a second module as a poster session; to the various people at that conference who offerred suggestions and encouragement; to Yves Gigon for putting together the video / music pairings, and to Harry Mountain, for daily support, encouragement, feedback, and inspiration.