@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.}
}
@article {tadashige1965operculated,
	title = {Operculated land molluscs from Southeast Asia},
	journal = {Nature and life in Southeast Asia},
	volume = {4},
	year = {1965},
	pages = {111-128},
	publisher = {Japan Society for the Promotion of Science},
	author = {Habe, T.}
}
