A summary of recent significant scientific and economic results accompanied by a list of geological and hydraulic investigations in progress and report on the status of topographic mapping 

 - Washington, D.C.  U.S. Geological Survey  1979 
 - 477 p. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>GEOLOGIA<br/>INVESTIGACION GEOLOGICA
<br/><br/><label>Subjects--Geographic Terms: </label><br/>ESTADOS UNIDOS