Secord, R. (2008). The Tiffanian land-mammal age (middle and late Paleocene) in the northern Bighorn Basin, Wyoming. Museum of Paleontology, University of Michigan.

Secord, Ross. The Tiffanian Land-mammal Age (middle and Late Paleocene) in the Northern Bighorn Basin, Wyoming. Ann Arbor, MI: Museum of Paleontology, University of Michigan, 2008.

Secord, Ross. The Tiffanian Land-mammal Age (middle and Late Paleocene) in the Northern Bighorn Basin, Wyoming. Museum of Paleontology, University of Michigan, 2008.