Verbatim text: Clausen, R.T. 1938. A monograph of the Ophioglossaceae. Mem. Torrey Bot. Club. 19(2): 1--177.
Author: Clausen, R.T.
Year: 1938
Title: A monograph of the Ophioglossaceae
Journal: Mem. Torrey Bot. Club
Volume: 19
Pages: 1–177