Michael Norris Harmonic Series Calculator
Michael Norris Frequency and Ring Mondulation Calculator
Kyle Gann's Just Intonation Explained
Just Intonation and Microtonal links
Marc-André Dalbavie publisher's site
Ricordi (Publisher) page on Gérard Grisey
Universal Editions's Haas page
Mike Searby's György Ligeti site
The Giacinto Scelsi Foundation