Drooyan, I. (1977). Essentials of trigonometry (2nd ed.). Macmillan Publishing.
Chicago Style (17. basım) AtıfDrooyan, Irving. Essentials of Trigonometry. 2nd ed. New York: Macmillan Publishing, 1977.
MLA (9th ed.) AtıfDrooyan, Irving. Essentials of Trigonometry. 2nd ed. Macmillan Publishing, 1977.
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