Roth, Barry, and Jeff Tupen. “Revision of the Systematic Status of Helminthoglypta walkeriana morroensis (Hemphill, 1911) (Gastropoda: Pulmonata)”. Zootaxa 616, no. 1 (August 25, 2004): 1–23. Accessed April 20, 2025. https://mapress.com/zt/article/view/zootaxa.616.1.1.