ZILL, D. G., & DEWAR, J. M. (1990). Trigonometry.-- Ed.2. McGraw-Hill.
Lua i Stíl Chicago (17ú heag.)ZILL, Dennis G., agus Jacqueline M. DEWAR. Trigonometry.-- Ed.2. New York: McGraw-Hill, 1990.
Lua MLA (9ú heag.)ZILL, Dennis G., agus Jacqueline M. DEWAR. Trigonometry.-- Ed.2. McGraw-Hill, 1990.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.