EARNST, Susan L; BART, Jonathan. Costs and benefits of extended parental care in Tundra Swans Cygnus columbianus columbianus. Wildfowl, [S. l.], p. 260–267, 2013. Disponível em: https://tidsskrift.dk/Wildfowl/article/view/154965. Acesso em: 23 jan. 2026.