1. Avers, P.E., Cleland, D.T., McNab, W.H., Jensen, M.E., Bailey, R.G., King, T., Goudey, C.B., Russell, W.E., 1994. National hierarchical framework of ecological units. US Department of Agriculture, Forest Service, Washington, DC.
2. Bailey, R.G., 1995. Description of the ecoregions of the United States. Second edition. Miscellaneous Publications No. 1391 (rev), US Department of Agriculture, Forest Service, Washington, DC.
3. Biogeography and conservation of taxa from remote regions: an application of ecological-niche based models and GIS to North-African canids;Brito;Biological Conservation,2009
4. Cade, B.S., 1986. Habitat suitability index models: Brown thrasher. Biological Report 82, US Fish Wildlife Service, Fort Collins, Colorado.
5. Atlas of the Breeding Birds of Wisconsin;Cutright,2006