Stucky, R.K. 1990. Evolution of Land Mammal Diversity in North America during the Cenozoic. Current mammalogy, 2:375-432.
Land Mammal diversity has changed dramatically since the extinction of the dinosaurs.
Woodburne, M., G, Gunnell and Richard Stucky. 2009. Land Mammal Faunas of North America Rise and Fall During the Early Eocene Climatic Optimum. Annals, Denver Museum of Nature & Science, No. 1.
Studies of rocks from 52 to 48 milllion years ago reveal a time period of global warming when patterns of species diversity changed.
Krishtalka, L., and R.K. Stucky. 1983a. Revision of the Wind River faunas, early Eocene of central Wyoming. Part 3. Marsupialia. Annals of Carnegie Museum, 52:205-227.
Krishtalka, L., and R.K. Stucky. 1983b. Paleocene and Eocene marsupials of North America. Annals of Carnegie Museum, 52:229-263.