Duffield, Wendell A. <br/><br/>
Tapping the earth’s natural heat / 
by Wendell A. Duffield, John H. Sass and Michael L. Sorey. 
 - [Washington]:   [United States Government Printing Office],   [1994].  
 - 63 p. :  ill., maps ;  28 cm. 
 -  1125 .
<br/><br/>Includes bibliographical references (p. 56-57). 
<br/><br/><label>ISBN: </label>
<br/><br/><label>Subjects--Topical Terms: </label><br/>Geothermal resources
<br/><br/><label>Dewey Class. No.: </label>333.88