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Beinert |
1971 |
Thalassoceratidae, Upper Paleozoic "Ceratitic" ammonoids.
Unpublished Ph.D. thesis, Department of Geology, University of Iowa, 1-249, 44 text-figs., 8 pls., Iowa City, IA.
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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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