H. Shaler Williams, ?On the revision of the mollusk genus Pterinea, Goldfuss?, Proceedings of the United States National Museum, vol. 34, pp. 83-90, 1908.

H. Shaler Williams, ?Some new Mollusca from the Silurian formations of Washington county, Maine?, Proceedings of the United States National Museum, vol. 42, pp. 381-398, pls. 49, 50, 1912.

H. Shaler Williams and Breger, C. Leventhal, ?The fauna of the Chapman Sandstone of Maine including descriptions of some related species from the Moose River Sandstone?, U.S. Geological Survey Professional Paper, vol. 89, pp. 1-347, 1916.

H. Shaler Williams, ?On the revision of the mollusk genus Pterinea, Goldfuss?, Proceedings of the United States National Museum, vol. 34, pp. 83-90, 1908.