A Comparison of Free Jazz to 20th Century Music
http://ccrma-www.stanford.edu/~blackrse/freejazz.html
This on line essay provides an overview of free jazz and compares it to modern classical composition. Twentieth Century Style
http://www.classicalscore.com/twentiethcenturystyle.htm
This site provides an excellent list of musical characteristics, with links on composers. | 