BirdLife International (2000) Threatened Birds of the World. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International.
NIKOLAUS, G. (1987) Distribution Atlas of Sudan’s Birds with notes on Habitat and Status. Bonner Zoologische Monographien, Nr. 25. Zoologisches Forschungsinstitut und Museum Alexander Koenig, Bonn.
ROBERTSON, P. Sudan chapter pp 877-890 in FISHPOOL, L.D.C. and EVANS M.I. editors (2001) Important Bird Areas in Africa and Associated Islands: Priority sites for conservation. Newbury and Cambridge, UK. Pisces Publications and BirdLife International (BirdLife Conservation Series No.11).
There is an excellent blog at Birding Sudan which gives interesting information on sightings in this underwatched country.
A complete species index and table of contents by author for Scopus volumes 1-25 (1977-2005) are now available in pdf format at scopus.
