Observations on the microscopic shell structure of Spirifer cuspidatus, Sowerby, and some similar American formsv. 17Academy of Natural Sciences275–277
Meek, F. B. and Worthen, A. H. 1865. "Observations on the microscopic shell structure of Spirifer cuspidatus, Sowerby, and some similar American forms." Proceedings of the Academy of Natural Sciences of Philadelphia, 17 275–277.