1969 Britannica yearbook of science and the future 
/ Encyclopaedia Britannica, Inc. 
 - Chicago:   Encyclopaedia Britannica, Inc.,   1968 
 - 447p. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Science
<br/><br/><label>Universal Decimal Class. No.: </label>R 5/6(058)  / K8