"FONTOSH!" = Important!
Mentioned are the European and American centers for computer music (IRCAM, Paris; Center for Computer Research in Music and Acoustics, Stanford University, California), the Mandelbrot equation, and the computer graphics of Manfred Eigen
Books of crucial importance are
Ernst Gombrich, The Sense of Order. A Study in the Psychology of Decorative Art
and
Douglas R. Hofstadter, Gödel, Escher, Bach: an Eternal Golden Braid.
Ligeti also mentions Maurits Cornelis Escher, whose optical illusions he was very fond of.

Keywords in German and Hungarian at the bottom of the page:
"Phase transitions = chaos-order-chaos"
"'Infinite' structures, CONFUSIONS, BOUNDARIES"
"MODERN - POSTMODERN → OTHER".