==Bibliography==* "Mammals and Winter Birds of Eastern Florida" (1871)* "The American Bisons", (1876)* "Monographs of North American Rodentia" (with Elliott Coues 1877)* "History of North American Pinnipedia" (1880)* "Mammals of Patagonia" (1905)* "The Influence of Physical Conditions in the Genesis of Species" (1905)* "Ontogenetic and Other Variations in Musk-Oxen" (1913)== References ====External links==* National Academy of Sciences Biographical Memoir
* Mammals and Winter Birds of Eastern Florida, (1871)* The American Bisons, (1876)* Monographs of North American Rodentia (with Elliott Coues, 1877)* History of North American Pinnipedia, (1880)* Mammals of Patagonia, (1905)* The Influence of Physical Conditions in the Genesis of Species, (1905)* Ontogenetic and Other Variations in Musk-Oxen (1913)