Template:Citation Style documentation/volume
From Global Energy Monitor
- volume: For one publication published in several volumes. Displays after the title and series fields; volume numbers should be entered just as a numeral (e.g. 37); volume values that are wholly digits, wholly uppercase roman numerals, or less than five characters will appear in bold. Any non-numeric value of five or more characters will be presumed to follow some other convention and will not appear in bold.