Plagiarism is the unaccredited use of another's ideas, thoughts or expressions as your own. Citing sources gives credit and shows where information used in writing originated. Understanding plagiarism gives assistance in learning how to avoid it and is an important part the of academic writing process.
Indiana University at Bloomington provides information on common collegiate plagiarism issues and ways to avoid them in the link below.
Purdue provides an online writing guide that contains learning information about the usage of citations.
The following books are located in print within the Henry G Bennett Library.
MLA Handbook for Writers of Research Papers by 
Publication Manual of the American Psychological Association by 
The Chicago Manual of Style by 
A Manual for Writers of Research Papers, Theses, and Dissertations by