Gupta , S.P. <br/><br/>
Statistical Methods 

 - New Delhi  Sultan Chand & Sons  1996 
 - 12-14.26p. 
<br/><br/><label>ISBN: </label>81-7014-065-X 
<br/><br/><label>Dewey Class. No.: </label>519.5   Gup.N6