Gude G. K. (1900). "Further notes on helicoid land shells from Japan, the Loo-Choo, and Bonin Islands, with descriptions of seven new species". Proceedings of the Malacological Society of London4: 70-80. page 75. Table VIII, figure 24-26.
Cowie R. H., Dillon R. T., Robinson D. G. & Smith J. W. (2009). "Alien non-marine snails and slugs of priority quarantine importance in the United States: A preliminary risk assessment". American Malacological Bulletin27: 113-132. PDFArchived 16 June 2016 at the Wayback Machine.
Cowie R. H., Dillon R. T., Robinson D. G. & Smith J. W. (2009). "Alien non-marine snails and slugs of priority quarantine importance in the United States: A preliminary risk assessment". American Malacological Bulletin27: 113-132. PDFArchived 16 June 2016 at the Wayback Machine.