Cita APA (7th ed.)

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

Cita Chicago (17th ed.)

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

Cita MLA (9th ed.)

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