BALTENSPERGER André, Iannis Xenakis und die Stochastische Musik. Komposition im Spannungsfeld von Architektur und Mathematik, Zürich, Paul Haupt, 1995, 709p.
Based on a Doctoral Dissertation defended in 1987. An in-depth study of earliest works, Metastaseis and works from the ST series. Three parts: 1) on Xenakiss earliest period: a) biography of his first steps; b) analyses of the works in question; c) Xenakiss work with Le Corbusier; d) analysis of Metastaseis; 2) study of the notion of stochastic music 3) analysis of the ST program and the ST works. The entire study is generously illustrated with diagrams and useful references. The analysis of Metastaseis is very detailed.
BIASE Salvatore di, Musica e matematica negli anni 50-60 : Iannis Xenakis, Bologne, Universida degli Studi di Bologna, 1994, 484p.