Cita APA (7th ed.)

Darwin, C., Barrett, P. H., & Freeman, R. B. (1988). The various contrivances by which orchids are fertilized by insects. Pickering.

Cita Chicago (17th ed.)

Darwin, Charles, Paul H. Barrett, i R. B. Freeman. The Various Contrivances by Which Orchids Are Fertilized by Insects. London: Pickering, 1988.

Cita MLA (8th ed.)

Darwin, Charles, et al. The Various Contrivances by Which Orchids Are Fertilized by Insects. Pickering, 1988.