APA (7th ed.) Citation

Simpson, A. (1989). dBase IV user's desktop companion. Sybex.

Chicago Style (17th ed.) Citation

Simpson, Alan. DBase IV User's Desktop Companion. San Francisco, CA: Sybex, 1989.

MLA (9th ed.) Citation

Simpson, Alan. DBase IV User's Desktop Companion. Sybex, 1989.