Cite both in-text and in the references list. Provide a citation every time you use someone else's ideas or words. This helps to avoid plagiarism - for more information, see the Okanagan College Avoiding Plagiarism Tutorial.
In-text (or parenthetical) citations are there to give credit to your source, and also to point your reader to the complete reference at the end of your paper.
References at the end of the paper help the reader find the source.
Remember to cite:
• Direct quotes
• Paraphrases
• Words or terminology specific to or unique to the author’s research, theories or ideas
• Use of an author's argument or original ideas
• Historical, statistical or scientific facts
• Graphs, drawings, etc.
• Articles or studies you refer to in your work
This list is from the UNC University Libraries Why We Cite list.