APA (7e ed.) Bronvermelding

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

Chicago (17e ed.) Bronvermelding

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

MLA (9e ed.) Bronvermelding

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