How To Choose & Place Punctuation To Close Quotations
Most academics and scientists are well aware that direct quotations must be enclosed in quotation marks except when they are displayed as block quotations and that the marks of punctuation used when introducing a quotation should be carefully chosen to present the borrowed material in the most effective manner. However, there tends to be considerable confusion regarding the punctuation that should be used immediately after direct quotations, a situation that leads to inconsistencies of various kinds at the end of quotations despite the fact that a tidy and consistent approach is what is needed in publishable scholarly writing.

Punctuation is not always required after a direct quotation, so there are instances in which the normal flow of a sentence can continue without punctuation, as in the following example: the guide advises that ‘every quotation should be checked for accuracy’ when proofreading a document. However, some form of punctuation is often needed immediately after quoted material. A sentence that finishes with a quotation must, like any other sentence, be closed with final punctuation, and a sentence that continues after the quotation it contains may require a comma or other punctuation mark immediately after the quotation. A full stop or comma that follows a quotation is usually placed inside the closing quotation mark in American English and in most fiction and journalism, whether American or British, as these examples demonstrate:
• The guide advises that ‘every quotation should be checked for accuracy.’
• Had the guide advised that ‘every quotation should be checked for accuracy,’ I would have proofread the quotations more carefully.
In British English, on the other hand, the full stop or comma is sometimes placed inside and sometimes outside the closing quotation mark depending on the nature of the quotation in relation to the structure of the entire sentence. If, for instance, you quote the end of a sentence, the full stop from that sentence would be included within the quotation mark, but if the borrowed text comes from the middle of a sentence, you would add your own full stop after the closing quotation mark. If the guidelines provided by a publisher indicate which of these two methods should be used for final punctuation associated with a quotation, follow them precisely and consistently throughout your document.

Colons, semicolons, dashes and parentheses normally appear outside closing quotation marks regardless of the method you are using. The only exception is when one of these pieces of punctuation is actually present in the source you have quoted, in which case it should be included within the closing quotation mark. The same principle applies to question and exclamation marks, and with these bits of punctuation, placement can significantly alter the meaning of a quotation and the sentence containing it. Notice, for instance, the difference in meaning between the following two examples:
• He actually meant it when he said, ‘So without patients the hospital would run much more smoothly’?
• He actually meant it when he said, ‘So without patients the hospital would run much more smoothly?’

The placement of punctuation after a quotation will also depend upon the format of the reference that follows the quotation. Parenthetical in-text references for embedded quotations usually precede any punctuation that follows a quotation, as the reference does in this example: the guide advises that ‘every quotation should be checked for accuracy’ (Smith 2013, p.6). When a quotation is displayed, the parenthetical reference may precede or follow the closing punctuation. Footnote or endnote numbers, on the other hand, generally follow the closing punctuation – the guide advises that ‘every quotation should be checked for accuracy’1 – while the numbers used for numerical references may precede or follow such punctuation depending on the specific guidelines you are using. Whichever method you use should be applied consistently in every relevant instance in your document.