Permian library
America
Alani-Pavon et al. 2025 - Permian ammonoids from the Guadalupian (Wordian–Capitanian) of Las Delicias, Coahuila state, Mexico new biostratigraphical and paleobiogeographical insight
Davis 1972 - Mature modification and dimorphism in selected Late Paleozoic Ammonoids
Miller and Furnish 1940 - Permian Ammonoids of the Guadalupe Mountain Region and Adjacent Areas
Miller and Youngquist 1947 - Lower Permian Cephalopods from the Texas Colorado river valley
Miller and Youngquist 1949 - American Permian Nautiloids
Nassichuk, Furnish and Glenister 1965 -The Permian ammonoids of arctic Canada
Spencer et al. 2014 - Nautiloids from the Early Permian Yeso Group, Otero County, New Mexico