Author
United States. Bureau of Chemistry and Soils
Pennsylvania State College. School of Agriculture
2
Atkinson, C. H. 1906-
1
Burke, R. T. Avon
1
Burke, R. T. Avon 1878-
1
Burke, R. T. Avon, 1878-
1
Hosterman, James L., 1909-
1
Marshall, R. M. 1907-
1
Simmons, C. S. 1900-
1
United States. Soil Conservation Service
1