14.159When to omit “vol.”
When a volume number is followed immediately by a page number, neither vol. nor p. or pp. is needed. The numbers alone are used, separated by a colon. A comma usually precedes the volume number, except with periodicals (see 14.180; see also 14.181) and for certain types of classical references (see 14.256–66). For more on volume numbers, see 14.121–27. For citing a particular volume, with and without the abbreviation vol., see 14.123.