APA (7th ed.) Citation

(1989). The Helios operating system (1. publ.). Prentice Hall.

Chicago Style (17th ed.) Citation

The Helios Operating System. 1. publ. New York u.a: Prentice Hall, 1989.

MLA (9th ed.) Citation

The Helios Operating System. 1. publ. Prentice Hall, 1989.