A citation (or reference) records the information necessary to finding the sources you consulted in your research. Common elements include the author's name, the year of publication, the publisher, the title of the journal in which an article was published, and the title of a book. In general, it is appropriate to cite the materials consulted in your research whenever they are used in your own work. Use of another's work could take the form of any of the following:
Providing a citation serves a number of purposes. By properly attributing ideas, opinions, and statistics to their authors, you avoid taking undeserved credit for them (plagiarism). It also allows the reader to confirm that you are representing others' work accurately. Finally, it serves as a starting point for those who are interested in exploring the topic further.