Professor Clark on 'The Feather Tracts of Swifts and Hummingbirds'
Shufeldt, Robert Wilson 1850-1934
Article
1906
The Auk
23
243--245
BioStor
English
Washington, D.C, American Ornithologists' Union, etc, 1884-
BioStor: https://biostor.org/reference/124314 DOI: https://doi.org/10.2307/4070788