Bl. William: Biographical article on this Cluniac, abbot of Hirschau, monastic reformer, astronomer, musician, who died in 1091. In the Catholic Encyclopedia.
Blessed William of Hirsau: Brief biography.
Hirschau: Much of this article in the New Schaff-Herzog Encyclopedia of Religious Knowledge is devoted to biographical information on Abbot William and the monastic reforms he introduced. Includes bibliography. Requires ability to view PNG files.