KRITSOV, S K; MINEYEV, Yu N. Daily time and energy budgets in Whooper Swans Cygnus cygnus and Bewick’s Swans Cygnus bewickii in the breeding season. Wildfowl, [S. l.], p. 319–321, 2013. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/154948. Acesso em: 17 dec. 2025.