J. Schafer

Arsenic, molybdenum, selenium, and tungsten contents of fertilizers and phosphate rocks

M. Tabatabai, R. Charter, J. Schafer, 1995 .

Soil geography and land use

J. Schafer, H. Foth, 1980 .

Metal contents of fertilizers marketed in Iowa

M. Tabatabai, R. Charter, J. Schafer, 1993 .