Authors Year Title
Nassichuk 1971 Permian ammonoids and nautiloids, Southeastern Eagle Plain, Yukon Territory.
Journal of Paleontology, 45 (6): 1001-1021, fig.1-12, tab.1-3, pl.124-126; Tulsa,Oklahoma.
Tharalson 1984 Revision of the Early Permian ammonoid family Perrinitidae.
Journal of Paleontology, 58 (3): 804-833, fig.1-24, 1tab.; Lawrence, Kansas.