APA (7th ed.) Citation

Kay, J., & Kummerfeld, B. (1989). C programming in a UNIX environment. National Book Store.

Chicago Style (17th ed.) Citation

Kay, Judy, and Bob Kummerfeld. C Programming in a UNIX Environment. Manila: National Book Store, 1989.

MLA (9th ed.) Citation

Kay, Judy, and Bob Kummerfeld. C Programming in a UNIX Environment. National Book Store, 1989.