Cita APA (7a ed.)

Ward, J. A., & Hetzel, H. R. (1980). Biology: Today and tomorrow. Minn West.

Cita Chicago Style (17a ed.)

Ward, Jack A., y Howard R. Hetzel. Biology: Today and Tomorrow. St. Paul.: Minn West, 1980.

Cita MLA (9a ed.)

Ward, Jack A., y Howard R. Hetzel. Biology: Today and Tomorrow. Minn West, 1980.