Buchanan,William. <br/><br/>
Understanting political variables. 

 - 4th  ed. 
 - London :  Macmillan,  1988. 
 - 387  p. ;    cm. 
<br/><br/>index. 
<br/><br/><label>ISBN: </label>9780023163609 :  $ 
<br/><br/><label>Subjects--Topical Terms: </label><br/>political science.