Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood (2015) The eBird/Clements checklist of birds of the world: Version 2015 http://www.birds.cornell.edu/clementschecklist/download, läst 2016-02-11
iucnredlist.org
oldredlist.iucnredlist.org
Birdlife International 2012 Sula sula Från: IUCN 2015. IUCN Red List of Threatened Species. Version 2015.4 www.iucnredlist.org. Läst 14 mars 2016.
iucnredlist.org
Birdlife International 2012 Sula sula Från: IUCN 2015. IUCN Red List of Threatened Species. Version 2015.4 www.iucnredlist.org. Läst 14 mars 2016.
wiley.com
onlinelibrary.wiley.com
Mayr, Gerald (2003): The phylogenetic affinities of the Shoebill (Balaeniceps rex). Journal für Ornithologie144(2): 157–175. HTML sammanfattning