1. Agricultural Research Service (2012) USDA plant hardiness zone map. U.S. Department of Agriculture. Available online: http://planthardiness.ars.usda.gov
2. Bailey RG (1974) Land capability classification of the Lake Tahoe Basin, California-Nevada: a guide for planning. USDA Forest Service in cooperation with the Tahoe Regional Planning Agency, South Lake Tahoe, CA. With separate map at three-quarter in. equal 1 mile
3. Bailey RG (1976) Map: ecoregions of the United States. USDA Forest Service, Intermountain Region, Ogden, UT. Scale 1:7,500,000
4. Bailey RG (1984) Testing an ecosystem regionalization. J Environ Manage 19:239–248
5. Bailey RG (1988) Problems with using overlay mapping for planning and their implications for geographic information systems. Environ Manage 12:11–17