1. Citations help others find the information you used in your research paper.
2. Citing your sources provides the original source of your material.
3. Citing your sources identifies materials in your bibliography.
4. Citing your sources gives credit to the person you quoted, summarized or paraphrased.
1. In your references or bibliography.
2. In the body of your text.
The practice of taking someone else's work or ideas and passing them off as your own is called plagiarism. (dictionary.com)
Any time you use ideas or words that appear in a document written by someone else, you must formally reference that work, even if it is not something that has been published.
You can avoid plagiarism by knowing what sources must be documented.
Specific words and phrases - If you use an author's specific words, you must place those words within quotation marks and you must credit the source.
Information and ideas - Even if you use your own words, if you obtained the information or ideas from a source, you must document the source.
You do not need to cite a source for material considered common knowledge (factual information about historical events considered to be in the public domain.)
When in doubt, cite!