1. Baker, K. (2016) Identification of European non-passerines. Second edition. BTO Books, Thetford.
2. Why are the wings of Larus f. fuscus so dark?;Bergman G.;Ornis Fennica,1982
3. Die Mauser der Schwungfedern beim Weissstorch Ciconia ciconia;Bloesch M.;Der Ornithologische Beobachter,1977
4. Bunzel, M. & Drüke, J. (1989) Kingfisher. In Lifetime reproduction in birds (ed Newton, I.), 107–116. Academic Press, London.
5. Cramp, S. (ed) (1985) Handbook of the birds of Europe, the Middle East and North Africa: the Birds of the Western Palearctic. Volume IV, Terns to Woodpeckers. Oxford University Press, Oxford.