Gaya APA

Drooyan, I. et al (1977). Essentials of Trigonometry (Ed. 2). New York: The Free Press A Division of Macmillan Publishing Co., INC..

Gaya MLA

Drooyan, Irving. et al. "Essentials of Trigonometry". Ed. 2 New York: The Free Press A Division of Macmillan Publishing Co., INC., 1977. Text.