@article {546,
	title = {Report on the cephalopods of the northeastern coast of America},
	year = {1882},
	month = {1879},
	publisher = {Rep. U.S. Comm. Fish.},
	author = {A.E. Verrill}
}
@article {541,
	title = {Vorl{\"a}ufige Mitteilung {\"u}ber die Thecosomata und Gymnosomata der Siboga-Expedition},
	journal = {Tijdsch. Nederl. Dierk.},
	volume = {2},
	year = {1903},
	pages = {117},
	chapter = {111},
	author = {J.J. Tesch}
}
@book {549,
	title = {Pseudothecosomata, gymnosomata and heteropoda (gastropoda)},
	year = {1976},
	pages = {484},
	publisher = {Bohn, Scheltema \& Holkeme Utrecht},
	organization = {Bohn, Scheltema \& Holkeme Utrecht},
	address = {Amsterdam},
	isbn = {9031301760},
	author = {S. Van Der Spoel}
}
