Bernhardsen, Tor. <br/><br/>
Geographic information systems :  an introduction / 
Tor Bernhardsen. 
 - 3rd  ed. 
 - New York :  J. Wiley,  2002. 
 - xiii, 428  p. 
<br/><br/><label>ISBN: </label>0471419680 : 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Geographic information systems.