• [Wiki] http://en.wikipedia.org/wiki/Pica_pica.
• [ADW] http://animaldiversity.org/accounts/Pica_hudsonia/.
• [AnAge] http://genomics.senescence.info/species/entry.php?species=Pica_pica.
• [Kooy2010] Kooijman, S. (2010). Dynamic Energy Budget theory for metabolic organisation. Cambridge Univ. Press, Cambridge.
• [PrinPres1991] Prinzinger, R., A.Preßmar, and Schleucher, E. (1991). Body temperature in birds. Comp. Biochem. Physiol., 99A(4):499--506. doi:10.1016/0300-9629(91)90122-S.
• [SoleSole1991] Soler, M. and Soler, J. J. (1991). Growth and development of great spotted cuckoos and their magpie host. The Condor, 93:49--54.