1. Juzhong Zhang, Garman Harbottle, Changsui Wang, and Zhaochen Kong: Oldest playable musical instrument found at Jiahu early neolithic site in China, Nature 401, 366 (1999).
2. The flutes are displayed and played on the web site of the Brookhaven National Laboratory: http: //www. bnl.gov/bnlweb/flutes. html.
3. René Descartes: Abrégé de Musique (Compendium Musicae, Utrecht, 1650; French translation by F. de Buzon published by PUF, Paris, 1987 ).
4. Jean Lattard: Gammes et Tempéraments (Diderot, Paris, 1997), and references therein.
5. Louis de Broglie: Recherches sur la Théorie des Quanta (Thesis, Paris Sorbonne, 1924), Ann. Phys. 10 III, 22 (1925).