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^Simonds, F. (1891). "The geology of Washington County". Arkansas Geological Survey Annual Report 1888. 4: 26, 49–53.
^Henry, Thomas W.; Gordon Jr., Mackenzie (1985). "Chesterian Davidsoniacean and Orthotetacean brachiopods, Ozark region of Arkansas and Oklahoma". Journal of Paleontology. 59 (1): 32–59.