Não informado. (1929). Butler University botanical studies. Butler University, Department of Botany.
Chicago-referens (17:e uppl.)Não informado. Butler University Botanical Studies. Indianapolis, Ind: Butler University, Department of Botany, 1929.
MLA-referens (8:e uppl.)Não informado. Butler University Botanical Studies. Butler University, Department of Botany, 1929.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.