@book{bhlpg40816872, title = {Bulletin of the British Ornithologists' Club }, volume = {v.89-90 (1969-1970)}, url = {https://www.biodiversitylibrary.org/page/40816872}, publisher = {British Ornithologists' Club}, author = {British Ornithologists' Club. }, year = {1969}, pages = {Page 138}, }