@inbook{ERMS:SourceID:166325, author = {Spoel, S. van der }, title = {Euthecosomata, a group with remarkable developmental stages (Gastropoda, Pteropoda). Gorinchem: Noorduijn en Zoon. 378 pp. [20 November 1967]}, url = {http://www.marbef.org/data/aphia.php?p=sourcedetails&id=166325}, year = {1967} }