| Authors(s) | Preston W.C. |
| Year | 1968 |
| Title | Breeding ecology and social behaviour of the Black Guillemot Cepphus grylle. Unpublished Ph.D. thesis, University of Michigan, Ann Arbor 138pp |
| Authors(s) | Preston W.C. |
| Year | 1968 |
| Title | Breeding ecology and social behaviour of the Black Guillemot Cepphus grylle. Unpublished Ph.D. thesis, University of Michigan, Ann Arbor 138pp |