Unlike enclosed letters in regular text, print punctuation is retained, and a letter sign is not used, for letters that designate topics within outlines and lists—whether items are listed vertically or horizontally. If, however, such letters are not in contact with punctuation, a letter sign is required. Examples:
| A. Thomas Edison
Refer to item [d] in the list.
Refer to item d in the list.
The court decided: a. Hays was guilty; b. it was a felony; c. a ten-year sentence.
Q: How long is the sentence, Mr. Hays?
A: Too long!
[Enclosed single-letter abbreviations and single letters in contact with a slash will be studied in Lesson 13.]