Verbatim text: Rollins, R. C. 1980b. The genus Pennellia (Cruciferae) in North America. Contr. Gray Herb. 210: 5–21.
Author: Rollins, R.C.
Year: 1980b
Title: The genus Pennellia (Cruciferae) in North America
Journal: Contr. Gray Herb
Volume: 210
Pages: 5–21