Flora Reipublicae Popularis Sinicae, volume 73(1)
The Domestic Encyclopædia; Or, A Dictionary Of Facts, And Useful Knowledge
Portál informačního systému ochrany přírody
Finnish Biodiversity Information Facility
Taxonomy database of the U.S. National Center for Biotechnology Information
Global Biodiversity Information Facility
United States Department of Agriculture Plants Database
The Vascular Plants of Iowa: An Annotated Checklist and Natural History