http://owl.english.purdue.edu/owl/resource/560/01/

I pasted the link to the Online Writing Lab (OWL) at Purdue University's section on APA formats. I think your instructor wants you to use APA citation style for the items (articles, books, etc.) that you are reviewing. In other words, you must cite the work in the format (APA) as part of your review. The OWL site will show examples for citing books, journal erticles, etc.

I hope this helps you out and answers your question. The OWL is a great resource for both APA and MLA citation styles.