by Arthur E. Taylor ... [and others] ; United States Department of Agriculture, Bureau of Plant Industry in cooperation with the University of Georgia, College of Agriculture
[by Russell R. Sanders ... and others] ; United States Department of Agriculture, Soil Conservation Service in cooperation with Texas Agricultural Experiment Station
by J. W. Moon ... [and others] ; United States Department of Agriculture, Bureau of Chemistry and Soils ; in cooperation with the Michigan Agricultural Experiment Station and the Michigan Department of Conservation, Land-Economic Survey
by P.R. McMiller ... [and others] ; United States Department of Agriculture, Bureau of Plant Industry ; in cooperation with the University of Minnesota Agricultural Experiment Station