Medieval political philosophy  a sourcebook 
edited by Ralph Lerner and Muhsin Mahdi 
 - New York  Free Press  1963 
 - xii, 532 p. ; 24 cm. 
<br/><br/>p. 527-528. 
<br/><br/><label>LCCN: </label>63-008419 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Political science<br/>Philosophy, Medieval