Evolution of the horse.
In two parts: Evolution of the horse in nature by W. D. Matthew, [and] The horse under domestication: its origin and the structure and growth of the teeth by S. H. Chubb.

APA Citation

American Museum of Natural History., Chubb, S. H., Matthew, W. Diller. (1921). Evolution of the horse: In two parts: Evolution of the horse in nature by W. D. Matthew, [and] The horse under domestication: its origin and the structure and growth of the teeth by S. H. Chubb. New York: The museum.

MLA Citation

American Museum of Natural History, S. H Chubb, and William Diller Matthew. Evolution of the Horse: In Two Parts: Evolution of the Horse In Nature by W. D. Matthew, [and] The Horse Under Domestication: Its Origin And the Structure And Growth of the Teeth by S. H. Chubb. New York: The museum, 1921.

Warning: These citations may not always be complete (especially for serials).