Butomus umbellatus - harilik luigelill Keilas.jpg
Brockhaus and Efron Encyclopedic Dictionary
Flora Reipublicae Popularis Sinicae, volume 8
The Domestic Encyclopædia; Or, A Dictionary Of Facts, And Useful Knowledge
Portál informačního systému ochrany přírody
Finnish Biodiversity Information Facility
The IUCN Red List of Threatened Species 2022.2
Taxonomy database of the U.S. National Center for Biotechnology Information
Global Biodiversity Information Facility
United States Department of Agriculture Plants Database