Cita APA (7th ed.)
Gottfried, S. S. (1993). Biology today. Mosby.
Cita Chicago (17th ed.)
Gottfried, Sandra S. Biology Today. Baltimore: Mosby, 1993.
Cita MLA (9th ed.)
Gottfried, Sandra S. Biology Today. Mosby, 1993.
Atenció: Aquestes cites poden no estar 100% correctes.