1. Dahl T. E. 1990. Wetlands Losses in the United States 1780's to 1980's. U.S. Department of the Interior Fish and Wildlife Service Washington DC 13. Dahl T. E. 1990. Wetlands Losses in the United States 1780's to 1980's. U.S. Department of the Interior Fish and Wildlife Service Washington DC 13.
2. Dahl T. E. and Johnson C. E. 1991. Status and Trends of Wetlands in the Conterminous United States Mid-1970's to Mid-1980's. U.S. Department of the Interior Fish and Wildlife Service Washington DC 28. Dahl T. E. and Johnson C. E. 1991. Status and Trends of Wetlands in the Conterminous United States Mid-1970's to Mid-1980's. U.S. Department of the Interior Fish and Wildlife Service Washington DC 28.
3. Dahl T. E. 2000. Status and Trends of Wetlands in the Conterminous United States 1986 to 1997. U.S. Department of the Interior Fish and Wildlife Service Washington DC 82. Dahl T. E. 2000. Status and Trends of Wetlands in the Conterminous United States 1986 to 1997. U.S. Department of the Interior Fish and Wildlife Service Washington DC 82.
4. United States Department of Agriculture -- Natural Resources Conservation Service. Nrcs.usda.gov. 2018. https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/ nrcs142p2_006812.pdf. United States Department of Agriculture -- Natural Resources Conservation Service. Nrcs.usda.gov. 2018. https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/ nrcs142p2_006812.pdf.
5. United States Department of Agriculture - Natural Resources Conservation Service: Report on CRP Practice CP8A. Nrcs.usda.gov. 2018. http://www.in.nrcs.usda.gov/programs/CRP/2012_job_sheet/ IN%20CP8A%20Program%20Sheet%20vMar1-0.pdf. United States Department of Agriculture - Natural Resources Conservation Service: Report on CRP Practice CP8A. Nrcs.usda.gov. 2018. http://www.in.nrcs.usda.gov/programs/CRP/2012_job_sheet/ IN%20CP8A%20Program%20Sheet%20vMar1-0.pdf.