APA (7th ed.) Citation
Roethel, L. F. (1965). To improve your grades in trigonometry (1a. ed.). Collier Books.
Chicago Style (17th ed.) Citation
Roethel, Louis F. To Improve Your Grades in Trigonometry. 1a. ed. New York: Collier Books, 1965.
MLA (9th ed.) Citation
Roethel, Louis F. To Improve Your Grades in Trigonometry. 1a. ed. Collier Books, 1965.
Warning: These citations may not always be 100% accurate.