Vinogradov, V. G., & Auezov, E. M. (2013). Numbers, distribution and breeding success of Whooper Swans Cygnus cygnus and Mute Swans C. olor in central Kazakhstan, USSR, in 1985 and 1987. Wildfowl, 73–76. Retrieved from https://tidsskrift.dk/Wildfowl/article/view/154998