Census of India,1971 <br/><br/>
Economic tables. V 9, Kerala. (Tables  Pt.II-B1 To B-IV) 

 - Kerala  Govt .Press           1971 
<br/><br/><label>Source: </label> General Book 
<br/><br/><label>Dewey Class. No.: </label>Y:5.212sN71, L1.9-2B1