Dutton, Geoffrey. <br/><br/>
First International Advanced Study Sympoisium on Topological Data Structures for Geographic Information Systems /  

 - 1st ed /  
 -   . 
 - p.121 :  
<br/><br/><label>ISBN: </label>0-89866-007-6 
<br/><br/><label>Dewey Class. No.: </label>Up1,N77  / L7.8