References

Archerd, gladys. 2008. Land Snails (& other Air-Breathers in Pulmonata Subclass & Sorbechocha Clade) Glady Archerd Shell Collection <URL: http://shells.tricity.wsu.edu/ArcherdShellCollection/Gastropoda/Pulmonates.html>. Accessed 30 March 2011.
Branson, B. 1972. The Recent Gastropoda of Oklahoma, III: Terrestrial species; Pupillidae, Carychlidae, Strobilpsidae, and Oligyridae. Southeastern Naturalist 16(3&4): 61-62.
Dall, W. 1905. Alaska, Volume XIII, Land and Fresh Water Mollusks. Doubleday, Page & Company. New York, USA. Pg 27.
Johnson, R. 2009. Dwight Blaney & William Procter on the Molluscan: Faunas of Frenchman Bay & Ironbound Island, Maine. Northeastern Naturalist 16(mo4):1-39.
Martin, S. 2000. Terrestrial Snail & Slugs (Mollusks: Gastropoda) of Maine. Northeastern Naturalist 7: 33-88.
Orstan, A. 1999. Land snails of Back Hills Regional Park, Montgomery County, Maryland. The Maryland Naturalist. Germantown Maryland, USA 43(3-4):20-24.
Nordsieck, robert. 2010. The reproduction of Gastropods. The Living World of Mollusks <URL: http://www.weichtiere.at/english/gastropoda/morphology/reproduction.html>. Accessed 30 March 2011.
Coppolino, M.L. 2009. Land Snails if Southern Illinois. Southern Illinois University, Carbondale, Illinois, USA. <URL: http://mypage.siu.edu/mlcopp>. Accessed on 30 March 2011.

Archerd, gladys. 2008. Land Snails (& other Air-Breathers in Pulmonata Subclass & Sorbechocha Clade) Glady Archerd Shell Collection <URL: http://shells.tricity.wsu.edu/ArcherdShellCollection/Gastropoda/Pulmonates.html>. Accessed 30 March 2011.