Cita APA (7th ed.)
Ehrlich, P. R., Holm, R. W., & Soulé, M. E. (1973). Introductory Biology. McGraw-Hill Book Company.
Cita Chicago (17th ed.)
Ehrlich, Paul R., Richard W. Holm, i Michael E. Soulé. Introductory Biology. New York: McGraw-Hill Book Company, 1973.
Cita MLA (9th ed.)
Ehrlich, Paul R., et al. Introductory Biology. McGraw-Hill Book Company, 1973.
Atenció: Aquestes cites poden no estar 100% correctes.