by M.K. Landon ... [and others] ; prepared in cooperation with the University of Minnesota Department of Soil, Water, and Climate, the U.S. Department of Agriculture, Agricultural Research Service, and the Minnesota Pollution Control Agency
by G.N. Delin ... [and others] ; prepared in cooperation with the University of Minnesota Department of Soil Science, the U.S. Department of Agriculture, Agricultural Research Service, and the Minnesota Pollution Control Agency