Library of Congress
Loc: The Gerry Mulligan Collection
A collection of scores, recordings, and memorabilia of the jazz great Gerry Mulligan.
Other
606 Club: Jazz Styles
This site provides a definition of the various types of jazz styles. A short definition of free jazz is provided close to the end of the page, along with several other forms, such as be-bop, west coast, hard-bop and mainstream.