@article {45, title = {The Malayan species of Opisthostoma (Gastropoda, Probranchia, Cyclophoridae), with a catalogue of all the species hitherto described}, journal = {The Bulletin of the Raffles Museum}, volume = {24}, year = {1952}, pages = {5-61}, chapter = {5}, url = {http://rmbr.nus.edu.sg/rbz/biblio/24/24brm005-062.pdf}, author = {van Benthem-Jutting, W.S.S.} } @article {37, title = {Additional new species and new localities of the family Vertiginidae and the genera Oophana and Opisthostoma from Malaya}, journal = {The Bulletin of the Raffles Museum}, volume = {26}, year = {1961}, pages = {34-48}, chapter = {34}, url = {http://rmbr.nus.edu.sg/rbz/biblio/26/26brm034-048.pdf}, author = {van Benthem-Jutting, W.S.S.} }