Gill, William R. <br/><br/>
Soil dynamics in tillage and traction / 
by William R. Gill and Glen E. Vanden Berg. 
 - [Washington] :  Agricultural Research Service, U.S. Dept. of Agriculture,  1967] 
 - viii, 511 p. :  ill. 
 - United States. Dept. of Agriculture. Agriculture handbook ;  no. 316 .
 - Agriculture handbook (United States. Dept. of Agriculture). .
<br/><br/><label>Subjects--Topical Terms: </label><br/>Soil dynamics.<br/>Tillage.<br/>Farm tractors.