1. The use of ecological classification in management;Carpenter,1999
2. Principles for ecological classification;Grossman,1999
3. Ecosystem characterization and ecological assessments;Bourgeron,2001
4. Ecoregions: the ecosystem geography of the oceans and the continents;Bailey,1988
5. Ecoregions, watersheds basins and HUCs: how state and federal agencies frame water quality;Griffith;Journal of Soil and Water Conservation,1999