Langson Library Music 201 page: books, article, scores
Richared Cohn, Audacious Euphony e-book
Supplementary materials for post-tonal review:
Straus, Introduction to Post-tonal theory, chapter 1
Joseph N. Straus on Centric music;
A Brief Guide to Mathematical theory
Brief handout on post-tonal theory
Gary Tucker's Brief Introduction to post-tonal theory
Glossary of PC set theory terms
Larry Solomon's Set theory primer