Raven, P. H., & Johnson, G. B. (1991). Understanding biology (2nd ed.). Wm. C. Brown Publishers.
Chicago Style (17th ed.) ZitazioaRaven, Peter H., eta George B. Johnson. Understanding Biology. 2nd ed. Dubuque, IA: Wm. C. Brown Publishers, 1991.
MLA (9th ed.) ZitazioaRaven, Peter H., eta George B. Johnson. Understanding Biology. 2nd ed. Wm. C. Brown Publishers, 1991.
Kontuz: berrikusi erreferentzia hauek erabili aurretik.