The standard APA guides (see Citation Styles and Guides) will help with articles and other standard sources, but some common business resources are not likely to be useful for psychology-related pursuits. You may not find many examples or specific guidelines. Just use your best judgement and be consistent. Here's an example for IBISWorld:
Publisher/Database as author. (Publication date). Title of report. Retrieved from URL
IBISWorld. (2012, Oct.). Frozen Yogurt Stores. Retrieved from http://www.ibisworld.com
For more help, the following guides (developed by librarians) provide additional examples and tips.
Let the databases do some of the work. Many of the databases on the Databases A-Z list have an internal feature that will produce a citation in various styles. Look for a link or icon titled "cite" or "save, print, email." You will have to check for accuracy, but it is a great way to get started.
Executive summaries are common in government and business, and it takes some practice to get them right. Here are some sources to help you write a good executive summary.