APA (7th ed.) Citation

Quercia, V., & O'Reilly, T. (1990). X Window System user's guide. O'Reilly & Associates.

Chicago Style (17th ed.) Citation

Quercia, Valerie, and Tim O'Reilly. X Window System User's Guide. Sebastopol, CA: O'Reilly & Associates, 1990.

MLA (9th ed.) Citation

Quercia, Valerie, and Tim O'Reilly. X Window System User's Guide. O'Reilly & Associates, 1990.