1. A rapid technique for aging grey squirrels in winter pelage;Barrier;J. Wildlife Manage.,1967
2. Clinal variation in white-throated swifts from Utah and the Rocky Mountain region;Behle;Auk,1973
3. Ueber die Verhältnisse der Wärmeökonomie der Thiere zu ihrer Grösse;Bergmann;Gottinger Studien,1847
4. Adaptive variation in the genus Vireo;Hamilton;Wilson Bull.,1958