Alfred L. Gardner, "Order Didelphimorphia," Mammal Species of the World, (3rd ed.), Volume 1, Don E. Wilson & DeeAnn M. Reeder (ed.), Volume 1, Johns Hopkins University Press, 2005, Pages 3 - 18.
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Frederick S. Szalay, “Taxa and phylogeny of Metatheria,” Evolutionary History of the Marsupials and an Analysis of Osteological Characters, Cambridge University Press, 1994, 277-406.