Knechtel, Maxwell M.  1897-1984 <br/><br/>
Bentonite deposits of the Northern Black hills district Wyoming, Montana, and South Dakota / 
by Maxwell M. Knechtel and Sam H. Patterson. 
 -- Washington :   United States Government Printing Office,   1962 
 - P. 893-1030 + map. -- 
 (Geological Survey Bulletin  ;  1082-M).
<br/><br/><label>Subjects--Topical Terms: </label><br/>Bentonita<br/>Estados Unidos<br/>Yacimientos de arcilla
<br/><br/><label>Universal Decimal Class. No.: </label>552.523(78)