Simpson, Howard E.  1917- <br/><br/>
Geology of the Yankton area south Dakota and Nebraska / 
by Howard E. Simpson. 
 -- Washington :   United States Government Printing Office,   1960 
 - 118 p. + 2 map. -- 
 (Geological Survey Professional Paper  ; 328).
<br/><br/><label>Subjects--Topical Terms: </label><br/>Dakota del Sur<br/>Geología<br/>Nebraska
<br/><br/><label>Universal Decimal Class. No.: </label>55(782/783)