Dahl, Robert Alan. <br/><br/>
Polyarchy :  participation and opposition. 

 - New Haven [CT] :  Yale University Press,  [1973] 
<br/><br/> First published in 1971. 
<br/><br/>Includes bibliographical references. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Opposition (Political science)<br/>Political participation.