@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 {535,
	title = {Pteropods},
	series = {South Atlantic Zooplankton},
	volume = {16},
	year = {1999},
	pages = {1706},
	publisher = {Leiden, Backhuys Publishers},
	organization = {Leiden, Backhuys Publishers},
	author = {J.R. Dadon and S. Van Der Spoel}
}
