APA (7th ed.) Citation

(1987). X/OPEN. Portability guide. Vol. 3. System V specification. Supplementary definitions ([1st ed.].). Elsevier Science Publishers.

Chicago Style (17th ed.) Citation

X/OPEN. Portability Guide. Vol. 3. System V Specification. Supplementary Definitions. [1st ed.]. Amsterdam: Elsevier Science Publishers, 1987.

MLA (9th ed.) Citation

X/OPEN. Portability Guide. Vol. 3. System V Specification. Supplementary Definitions. [1st ed.]. Elsevier Science Publishers, 1987.