Gill, William R. creator Vanden Berg, Glen E. creator text New Delhi Scientific Publishers (India) 2013 monographic viii, 511 p. illus. Agricultural Research Service, U.S. Dept. of Agriculture; [for sale by the Supt. of Docs., U.S. Govt. Print. Off., Soil dynamics Tillage Farm tractors 631.51 GIL/SO 9788172338039