G. W.  Tryon, Manual of conchology, structural and systematic : with illustrations of the species, vol. 2(2). Philadelphia: , 1886, p. 265.

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.

E. A.  Smith, ?On a collection of land-shells from Sarawak, British North Borneo, Palawan, and other neighbouring islands?, Proceedings of the Zoological Society of London, vol. 1895, pp. 97?127, 1895.

G. W.  Tryon, Manual of conchology, structural and systematic : with illustrations of the species, vol. 2(9). Philadelphia: , 1894, p. 366.