APA (7th ed.) Citation

(1984). Directory of public domain (and user-supported) software for the IBM personal computer. PC Software Interest Group.

Chicago Style (17th ed.) Citation

Directory of Public Domain (and User-supported) Software for the IBM Personal Computer. Santa Clara, Calif.: PC Software Interest Group, 1984.

MLA (9th ed.) Citation

Directory of Public Domain (and User-supported) Software for the IBM Personal Computer. PC Software Interest Group, 1984.