Cita APA (7th ed.)

Cohen, D. (1994). Precalculus with unit-circle trigonometry (2nd ed.). West Publishing Company.

Cita Chicago (17th ed.)

Cohen, David. Precalculus with Unit-circle Trigonometry. 2nd ed. Minneapolis, NY: West Publishing Company, 1994.

Cita MLA (9th ed.)

Cohen, David. Precalculus with Unit-circle Trigonometry. 2nd ed. West Publishing Company, 1994.