The following bibliography has been generated by bringing together all references provided by our content partners. There may be duplication.

References

• 1. IUCN Red List (January, 2009) http://www.iucnredlist.org/
• 10. Angehr, G., Schmidt, B., Njie, F., Christy, P., Gebhard, C., Tchignoumba, L. and Ombenotori, M.A.E. (2006) Bird surveys in the Gamba Complex of Protected Areas, Gabon. In: Alonso, A., Lee, M.E., Campbell, P., Pauwels, O.S.G. and Dallmeier, F. Eds. Gamba, Gabon: Biodiversity of an Equatorial African Rainforest. Bulletin of the Biological Society of Washington, No. 12.
• 2. del Hoyo, J., Elliott, A. and Sargatal, J. (1994) Handbook of the Birds of the World. Volume 2: New World Vultures To Guineafowl. Lynx Edicions, Barcelona.
• 3. Ferguson-Lees, J. and Christie, D.A. (2001) Raptors of the World. Helm Identification Guides, A & C Black Publishers, London.
• 4. CITES (January, 2009) http://www.cites.org/
• 5. Sinclair, I. and Davidson, I. (2006) Sasol Southern African Birds: A Photographic Guide. Struik, Cape Town.
• 6. BirdLife International (January, 2009) http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=3412&m=0
• 7. Boshoff, A.F. (1997) Gymnogene. In: Harrison, J.A., Allan., D.G., Underhill, L.G., Herremans, M., Tree, A.T., Parker, V. and Brown, C.J. Eds. The Atlas of Southern African Birds. Volume I. BirdLife South Africa, Johannesburg. Available at http://sabap2.adu.org.za/docs/sabap1/169.pdf
• 8. Burton, P.J.K. (1978) The intertarsal joint of the harrier-hawks Polyboroides spp. and the crane hawk Geranospiza caerulescens. Ibis, 120 (2): 171 - 177.
• 9. African Convention on the Conservation of Nature and Natural Resources (January, 2009) http://www.africa-union.org/root/au/Documents/Treaties/Text/Convention_Nature%20&%20Natural_Resources.pdf
• BirdLife International 2009. Polyboroides typus
• Gill, Frank, and Minturn Wright. 2006. Birds of the World: Recommended English Names. ix + 259