You must use citations when:
When in doubt, cite it!
The joy of finding footnotes and bibliographic entries that lead to the perfect original source can only happen when scholars carefully track their sources and generate citations in an appropriate style. Neglecting to track your sources as you move through the research process will cost you HOURS of precious time.
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When writing this paper, you will be using the MLA format. MLA uses parenthetical references (instead of footnotes). If you have any questions, please see a librarian at the help desk for assistance with using the MLA Handbook.
When using MLA style, you are expected to use in-text citations as opposed to footnotes. These can appear tricky at first, but honing the skill of in-text citations will actually make your writing stronger and more "readable" because they help eliminate passive voice writing.
Here are a few online guides that can help you with in-text citations: