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Miller, Furnish & Clark |
1957 |
Permian ammonoids from Western United States.
Journal of Paleontology, 31 (6): 1057-1068, fig.1-6, pl.133-134; Tulsa,Oklahoma.
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Tharalson |
1984 |
Revision of the Early Permian ammonoid family Perrinitidae.
Journal of Paleontology, 58 (3): 804-833, fig.1-24, 1tab.; Lawrence, Kansas.
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