Woodring, W. (1970). Geology and paleontology of Canal Zone and adjoining parts of Panama; description of Tertiary mollusks (Gastropods: Eulimidae, Marginellidae to Helminthoglyptidae). USGS Professional Paper. 306-D.
Geology and paleontology of Canal Zone and adjoining parts of Panama; description of Tertiary mollusks (Gastropods: Eulimidae, Marginellidae to Helminthoglyptidae)