@book {575,
	title = {Catalogue of the Mollusca in the collection of the British Museum, 2},
	series = {Pteropoda},
	volume = {4},
	year = {1850},
	pages = {45},
	publisher = {British Museum, E. Newman},
	organization = {British Museum, E. Newman},
	address = {London},
	author = {J.E. Gray}
}
@book {554,
	title = {Euthecosomata, a group with remarkable developmental stages (Gastropoda, Pteropoda)},
	year = {1967},
	pages = {375},
	publisher = {J. Noorduyn \& ZN, Gorinchem},
	organization = {J. Noorduyn \& ZN, Gorinchem},
	author = {S. Van Der Spoel}
}
@book {534,
	title = {Elements of ecology},
	year = {1954},
	pages = {534},
	publisher = {John Wiley},
	organization = {John Wiley},
	address = {New York},
	author = {G.L. Clarke}
}
