@article {688,
	title = {Catalog der gegenw{\"a}rtig lebend bekannten Pneumonopomen},
	journal = {Nachrichtsblatt der Deutschen Malakozoologischen Gesellschaft},
	volume = {30},
	year = {1898},
	chapter = {134},
	url = {http://biodiversitylibrary.org/item/89671$\#$page/336/mode/1up},
	author = {W. Kobelt and O. von Moellendorff}
}
@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.}
}
