H. H.  Godwin-Austen, ?On a Collection of Land-Shells made in Borneo by Mr. A. Everett, with Descriptions of supposed new Species. Part II. Zonitidae and Helicidae.?, Proceedings of the Zoological Society of London, pp. 22-47, 1891.

W. S. Svan Benthe Jutting, ?Systematic studies on the non-marine Mollusca of the Indo-Australian Archipelago?, Treubia, vol. 20, pp. 381-505, 1950.