Harary, Frank. <br/><br/>
Structural models :  an introduction to the theory of directed graphs / 
[by] Frank Harary, Robert Z. Norman [and] Dorwin Cartwright. 
 - New York :  Wiley,  [1965] 
<br/><br/>Bibliography: p. 392-395. 
<br/><br/><label>LCCN: </label>65012710 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Social sciences -- Mathematical models.--Social sciences -- Mathematical models.
<br/><br/><label>LC Class. No.: </label>H61  / .H287 
<br/><br/><label>Dewey Class. No.: </label>301.8