2 literature references for Oenopota regulus (Dall, 1919):

Year: 1996
Source: database, NODC Taxonomic Code
Author: Turgeon, D. D., J. F. Quinn, Jr., A. E. Bogan, E. V. Coan, F. G. Hochberg, W. G. Lyons, et al.
Year: 1998
Title: Common and scientific names of aquatic invertebrates from the United States and Canada: Mollusks, 2nd ed.
Source: American Fisheries Society Special Publication 26