1. Cramp S. Simmons K. E. L. (1977): Handbook of the Birds of Europe, the Middle East and North Africa: The Birds of the Western Palaearctic, Vol. 1: Ostrich to Ducks. – Oxford
2. Scott D. A. (1964): Notes on spring migration at the Bosphorus (unpublished) – In: Collman & Croxall (1967)