• [Wiki] http://en.wikipedia.org/wiki/Cygnus_cygnus.
• [AnAge] http://genomics.senescence.info/species/entry.php?species=Cygnus_cygnus.
• [ADW] https://animaldiversity.org/accounts/Cygnus_cygnus/.
• [Kooy2010] Kooijman, S. (2010). Dynamic Energy Budget theory for metabolic organisation. Cambridge Univ. Press, Cambridge.
• [Preu1973] Preuss, B. (1973). Breeding the whooper swan Cygnus cygnus cygnus at Rostock Zoo. International Zoo Yearbook, 13:41--43. doi:10.1111/j.1748-1090.1973.tb02099.x.