Ewins, P., Ewins, P., & Perrins, C. (1986). The ecology of black guillemots Cepphus grylle in Shetland.
Chicago-čujuhus (17. p.)Ewins, P., Pete Ewins, juo C. Perrins. The Ecology of Black Guillemots Cepphus Grylle in Shetland. 1986.
MLA-čujuhus (9. p.)Ewins, P., et al. The Ecology of Black Guillemots Cepphus Grylle in Shetland. 1986.
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