Studies of Central American plants. by Paul C. Standley and Julian A. Steyermark.

v.22:no.4(1940)

Phylogenetic studies of North American minnows : with emphasis on the genus Cyprinella (Teleostei, Cypriniformes) / by Richard L. Mayden.

no.80 (1989)

Studies of American plants. by Paul C. Standley.

v.22:no.3(1940)