Cita APA (7th ed.)

Drooyan, I., Hadel, W., & Carico, C. C. (1977). Essentials of trigonometry. Macmillan.

Cita Chicago (17th ed.)

Drooyan, Irving, Walter Hadel, i Charles C. Carico. Essentials of Trigonometry. New York: Macmillan, 1977.

Cita MLA (9th ed.)

Drooyan, Irving, et al. Essentials of Trigonometry. Macmillan, 1977.