Brilliant Granule (Guppya sterkii).  Wisconsin Department of Natural Resources 2011. <URL:>.  Accessed 6 October 2011.

Fournie, J. and M. Chetail.  1976.  Calcium Dynamics in Land Gastropods.  Integrative and Comparative Biology 24:857-870.

Guppya sterkii.  BayScience Foundation 2009.  <URL:  Accessed 8 November 2011.

Guppya sterkii.  ITIS Report 2011.  <URL: >.  Accessed 9 November 2011.

Guppya sterkii (Sterki's granule).  Michigan Natural Features Inventory 2011.  <URL:>.  Accessed 7 October 2011.

Hickman Jr, C.P, L.S. Roberts, S.L Keen, A. Larson and D.J. Eisenhower. 1972. Animal Diversity. McGraw Hill, New York, New York, USA.

Hubricht, L. 1985.  The Distribution of the Native Land Molluscs of Eastern United States.  Fieldiana Zoology 24, 191: 142.

Hyman, I.T., S.Y.W. Ho and L.S. Jermiin. 2007.  Molecular Phylogeny of Australian Helicarionidae, Euconulidae and Related Groups (Gastropoda: Pulmonata: Stylommatophora) Based on Mitochondrial DNA.  Molecular Phylogenetics and Evolution 45: 792-812.

Land Snail Ecology: Land Snails and Forest Calcium.  Carnegie Museum of Natural History 2011. <URL:>.  Accessed 10 November 2011.

Nekola, J.C. 2003.  Large-scale terrestrial gastropod community composition patterns in the Great Lakes region of North America.  Diversity and Distributions A Journal of Conservation Biogeography 9: 55-71.

Nekola, J.C. 2004.  Terrestrial Gastropod Fauna of Northeastern Wisconsin and the Southern Upper Penisula of Michigan.  American Malacological Bulletin 18: 21-44.

Williamson, P. and R.A.D. Cameron.  1976.  Natural Diet of the land snail Cepaea nemoralis.  Oikos 27: 493-500.