APA (7th ed.) Citation

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

Chicago Style (17th ed.) Citation

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

MLA (9th ed.) Citation

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