Cita APA (7a ed.)
Raven, P. H., & Johnson, G. B. (1991). Understanding biology (2nd ed.). WCB Brown Publishers.
Cita Chicago Style (17a ed.)
Raven, Peter H., y George B. Johnson. Understanding Biology. 2nd ed. Dubuque: WCB Brown Publishers, 1991.
Cita MLA (9a ed.)
Raven, Peter H., y George B. Johnson. Understanding Biology. 2nd ed. WCB Brown Publishers, 1991.
Precaución: Estas citas no son 100% exactas.