Helly, Walter <br/><br/>
Urban systems models / 
Walter Helly 
 - New York :  Academic Press,  1975 
 - x, 185 p. :  ill. ;  24 cm. 
 - Operations research and industrial engineering .
<br/><br/> Includes index 
<br/><br/><label>ISBN: </label>0123394503 :  USD 16.50 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Cities and towns--Mathematical models
<br/><br/><label>Dewey Class. No.: </label>301.360812