Cita APA

Ewins, P., Ewins, P., & Perrins, C. (1986). The ecology of black guillemots Cepphus grylle in Shetland.

Citación estilo Chicago

Ewins, P., Pete Ewins, and C. Perrins. The Ecology of Black Guillemots Cepphus Grylle in Shetland. 1986.

Cita MLA

Ewins, P., et al. The Ecology of Black Guillemots Cepphus Grylle in Shetland. 1986.