Student's guide to writing college papers, Fourth edition - Kate L. Turabian 2010
When you must cite a source
Citations
Citing sources
You must include a citation every time you use the words, ideas, or distinctive methods of a source (see 10.3). In particular, include a citation every time you use a source in these three ways:
✵ You quote the exact words of a source, including single words or phrases if they are distinctive enough. You must also indicate every quotation with quotation marks or a block indent.
✵ You paraphrase the words of a source.
✵ You use distinctive ideas or methods you found in a source.