The new encyclopaedia Britannica :  knowledge in depth / 
Encyclopedia Britannica. 
 - 15th ed. 
 - Chicago :  Encyclopedia Britannica,  c1990 
 - Vols. ;  29 cm. 
<br/><br/>V.-21 (Macropedia) 
<br/><br/>31  31 
<br/><br/><label>ISBN: </label>0852295111 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Encyclopedia
<br/><br/><label>Dewey Class. No.: </label>032/ N43