Verbatim text: Eckenwalder, J. E. 1977. North American cottonwoods (Populus, Salicaceae) of sections Abaso and Aigeiros. J. Arnold Arbor. 58: 193–208.
Author: Eckenwalder, J.E.
Year: 1977
Title: North American cottonwoods (Populus, Salicaceae) of sections Abaso and Aigeiros
Journal: J. Arnold Arbor
Volume: 58
Pages: 193–208
BHL link: http://www.biodiversitylibrary.org/part/29239