Verma. R. K. <br/><br/>
Ray Optics 
R. K. Verma 
 - 1st 
 - New Delhi  Discovery Publishing  2006 
 - 341 
<br/><br/><label>ISBN: </label>81-8356-113-6 
<br/><br/><label>Dewey Class. No.: </label>523.0153