1. Extraterrestrial cause for the Cretaceous–Tertiary extinction;Alvarez;Science,1980
2. Baars, D.L., 1988. Triassic and older stratigraphy, Southern Rocky Mountains and Colorado Plateau, ch. 4. In: Sloss, L.L. (Ed.), Sedimentary Cover – North American Craton. The Geology of North America, vol. D-2. Geological Society of America, Boulder, CO, pp. 53–64.
3. Babcock, J.A., 1977. Calcareous algae, organic boundstones, and the genesis of the upper Capitan Limestone (Permian, Guadalupian), Guadalupe Mountains, west Texas and New Mexico. In: Hileman, M.E., Mazullo, S.J. (Eds.), Upper Guadalupian Facies, Permian Reef Complex, Guadalupe Mountains, New Mexico and west Texas. Permian Basin Section. SEPM Publication 77-6, pp. 3–44.
4. Carboniferous and Permian stratigraphy and paleontology, Northern Yukon Territory, Canada;Bamber;Bull. Can. Pet. Geol.,1971
5. Barron, E.J., Fawcett, P.J., 1995. The climate of Pangea: a review of climate model simulations of the Permian. In: Scholle, P.A., Peryt, T., Ulmer-Scholle, D.S. (Eds.), The Permian of Northern Pangea, vol. 2: Paleogeography, Paleoclimates, Stratigraphy. Springer, Heidelberg, pp. 37–52.