It is important to cite sources to give credit to the authors of works and also to provide researchers with the means to track down your sources.
There are a number of style guides for formatting citations. Among these are Chicago and Turabian (a simplified version of Chicago). These styles are often used in the arts and social sciences.
Careful documentation of your work through citing is an effective way to avoid plagiarism.
[zoh-TAIR-oh] is a free, easy-to-use Firefox extension to help you collect, manage, cite, and share your research sources. It lives right where you do your work - in the web browser itself.