International encyclopedia of social sciences; v.12.   
ed. by David L. Sills 
 - London  Macmillan and Co.  1968 
 - 638p. 
<br/><br/><label>LCCN: </label>68-10023 
<br/><br/><label>Dewey Class. No.: </label>300.3  / N68.12 "R"