APA (7th ed.) Citation

International Business Machines Corporation. (1987). Disk operating system version 3.30: Reference (Version 3.30.). International Business Machines Corp.

Chicago Style (17th ed.) Citation

International Business Machines Corporation. Disk Operating System Version 3.30: Reference. Version 3.30. Boca Raton, Fla: International Business Machines Corp, 1987.

MLA (9th ed.) Citation

International Business Machines Corporation. Disk Operating System Version 3.30: Reference. Version 3.30. International Business Machines Corp, 1987.