Poicephalus gulielmi -Birds of Eden -South Africa-8a-3c.jpg
Poicephalus gulielmi -pair in captivity -3c.JPG
Poicephalus gulielmi - subspecies ranges in Africa.jpg
Global Biodiversity Information Facility
The IUCN Red List of Threatened Species 2021.3
Taxonomy database of the U.S. National Center for Biotechnology Information
Interim Register of Marine and Nonmarine Genera
Clements Checklist of Birds of the World