ARDAMATSKAYA, T B; KORZYUKOV, A I. Numbers and distribution of Mute Swans Cygnus olor Whooper Swans C. cygnus and Bewick’s Swans C. bewickii in the Black Sea area of the Ukraine, USSR. Wildfowl, [S. l.], p. 53–55, 2013. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/155007. Acesso em: 17 dec. 2025.