To quote a source, you must ensure that the quoted text is enclosed in quotation marks or formatted as a block quote. The original author is correctly cited and the text is identical to the original. The exact format of a quote depends on its length and on which citation style you are using.
When quoting within a quote, use single quotation marks within double quotation marks. This structure is called a nested quotation, which follows a hierarchy of alternating between double and single quotes.
