The Borrego mountain Earthquake of april 9, 1968. 

 -- Washington :   United States Government Printing Office,   1972 
 - 207 p. -- 
 (Geological Survey Professional Paper  ; 787).
<br/><br/><label>Subjects--Topical Terms: </label><br/>California<br/>Geología
<br/><br/><label>Universal Decimal Class. No.: </label>55(794)