A manual for writers of research papers, theses, and dissertations, 7th edition - Kate L. Turabian 2007

Quotation marks
Spelling
Part III. Style 20 spelling

For the use of quotation marks in quoted material, see 25.2.1. For use in titles and other special situations, see 22.3.2. For use in citations, see 16.1.4 and 18.1.4.

Some fields—linguistics, philosophy, and theology, for example—use single quotation marks to set off words and concepts. The closing quotation mark should precede a comma or period in this case (see 21.11.1).

kami ’hair, beard’

The variables of quantification, ’something’, ’nothing’, . . .

In most other fields, follow the guidelines in 22.2.2 for using quotation marks and italics with definitions of terms.