• [Wiki] http://en.wikipedia.org/wiki/Lutra_lutra.
• [AnAge] http://genomics.senescence.info/species/entry.php?species=Lutra_lutra.
• [ADW] http://animaldiversity.ummz.umich.edu/accounts/Lutra_lutra/.
• [Kooy2010] Kooijman, S. (2010). Dynamic Energy Budget theory for metabolic organisation. Cambridge Univ. Press, Cambridge.
• [Step1957] Stephens, M. N. (1957). The otter report. Universities Federation Animal Welfare, Herts.