Verbatim text: Johnson, M. F. 1971. A monograph of the genus Ageratum L. (Compositae–Eupatorieae). Ann. Missouri Bot. Gard. 58: 6–88.
Author: Johnson, M.F.
Year: 1971
Title: A monograph of the genus Ageratum L. (Compositae–Eupatorieae)
Journal: Ann. Missouri Bot. Gard
Volume: 58
Pages: 6–88
BHL link: http://www.biodiversitylibrary.org/part/7882