Here’s some resources for online American Psychological Association (APA) style referencing:
1. USM Libraries – APA STYLE GUIDE 5th Edition
2. California State University Library offers this “Style Manuals & Writing Guides” online, as well as a PDF file for download too.
3. The official APA Style for Electronic References goes here.
4. Here’s a reference for Web Extension to American Psychological Association Style (WEAPAS).