Using wikipedia

You can use wikipedia as a source if you've taken the usewiki quiz and become a contributor.  And of course you want to use quality pages. What is a quality page? Below are a few. They reference a variety of sources--some academic, others established magazines and journals. They are fairly stable and don't show recent edit wars. The prose is clear, the content well-organized.

Star-craft: Ghost
The Spanish Conquest of Guatemala
The Concert in Central Park
Craters of the Moon National Monument and Preserve