@book {694,
	title = {Monographia Pneumonopomorum viventium. Sistens descriptiones systematicas et criticas omnium hujus ordines generum et specierum hodie cognitarum, accedente fossilium enumeratione},
	volume = {3},
	year = {1865},
	pages = {284},
	url = {http://www.biodiversitylibrary.org/item/41632$\#$page/65/mode/1up},
	author = {L. Pfeiffer}
}
@article {1485,
	title = {Revision der Familien und Gattungen der Pneumonopomen},
	journal = {Malakozoologische Bl{\"a}tter},
	volume = {23},
	year = {1867},
	pages = {77-86},
	chapter = {77},
	url = {http://www.biodiversitylibrary.org/page/15854492$\#$page/107/mode/1up},
	author = {L. Pfeiffer}
}
@book {707,
	title = {Monographia heliceorum viventium, sistens descriptiones systematicas et criticas omnium hujus familiae generum et specierum hodie cognitarum},
	volume = {6},
	year = {1868},
	pages = {598},
	address = {Lipsiae},
	url = {http://www.biodiversitylibrary.org/bibliography/12727},
	author = {L. Pfeiffer}
}
@book {686,
	title = {Monographia Pneumonopomorum viventium, accedente fossilium enumeratione. Supplementum tertium. Monographiae Auriculaceorum. Parte secunda auctum},
	volume = {4},
	year = {1876},
	pages = {479 pp.},
	publisher = {Cassellis},
	organization = {Cassellis},
	author = {L. Pfeiffer}
}
