Q. A vertical list lettered with “a.,” “b.,” “c.,” etc. (using periods after each letter) is provided in a document. Later on in the write-up, I reference this list with the sentence, “[Name] has managed projects that cover items a through f.” Do “a” and “f” require some kind of punctuation or special treatment?
A. To refer to a lettered list item, you can normally use italics regardless of how the letters are punctuated in the list itself. For example, you could refer to item a or, if the letters in the list are capitals, item A. This is an application of the rule about using italics to refer to letters as letters (see CMOS 7.64). To refer to a number, on the other hand, use regular type regardless of whether the numerals are arabic or roman: item 1, item I, item i.
But if the letters or numbers in the list are in parentheses, then you can use parentheses in the text: item (a), item (i). One advantage of this approach is that lowercase letters and roman numerals in particular are easier to read when placed in parentheses. Whichever choice you make, be consistent.