APA (7th ed.) Citation

Drooyan, I. (1977). Essentials of trigonometry (2nd ed.). Macmillan Publishing.

Chicago Style (17th ed.) Citation

Drooyan, Irving. Essentials of Trigonometry. 2nd ed. New York: Macmillan Publishing, 1977.

MLA (9th ed.) Citation

Drooyan, Irving. Essentials of Trigonometry. 2nd ed. Macmillan Publishing, 1977.