APA (7th ed.) Citation
Mathematical Association of America, ebrary, Inc, Wells, D., & Faires, J. D. (2008). The contest problem book IX: American Mathematics Competitions (AMC 12) 2001-2007. Mathematical Association of America.
Chicago Style (17th ed.) Citation
Mathematical Association of America, Inc ebrary, Dave Wells, and J. Douglas Faires. The Contest Problem Book IX: American Mathematics Competitions (AMC 12) 2001-2007. Washington, D.C.: Mathematical Association of America, 2008.
MLA (9th ed.) Citation
Mathematical Association of America, et al. The Contest Problem Book IX: American Mathematics Competitions (AMC 12) 2001-2007. Mathematical Association of America, 2008.
Warning: These citations may not always be 100% accurate.