Messer M.; Weiss A.S.; Shaw D.C.; Westerman M. (March 1998). "Evolution of the Monotremes: phylogenetic relationship to marsupials and eutherians, and estimation of divergence dates based on α-Lactalbumin Amino Acid Sequences". Journal of Mammalian Evolution. 5 (1): 95–105. doi:10.1023/A:1020523120739. S2CID39638466.
"Venom". Australian Playpus Conservancy. Archived from the original on 2019-04-29. Retrieved 2019-05-15.
semanticscholar.org
api.semanticscholar.org
Messer M.; Weiss A.S.; Shaw D.C.; Westerman M. (March 1998). "Evolution of the Monotremes: phylogenetic relationship to marsupials and eutherians, and estimation of divergence dates based on α-Lactalbumin Amino Acid Sequences". Journal of Mammalian Evolution. 5 (1): 95–105. doi:10.1023/A:1020523120739. S2CID39638466.
web.archive.org
"Platypus". Department of Primary Industries and Water, Tasmania Online. Archived from the original on 2006-10-09. Retrieved 2008-12-23.