Crock J. G. <br/><br/>
Four Reference Soil And Rock Samples for Measuring Element Availability in the Western Energy Regions :  / 
J. G. Crock and R. C. Severson 
 - Washington, D.C. :  United States Geological Survey,  1980 
 - iii. 16 p. :  26 p. 
 - Geological Survey Circular ;  841 .
<br/><br/><label>Subjects--Topical Terms: </label><br/>Geology--Washington Metropolitan Area--United States<br/>Geological surveys--United States--History
<br/><br/><label>Dewey Class. No.: </label>557.30973