VEDAVALLI, V. R. <br/><br/>
Headway Science 7c 

 - New Delhi  Vikas pub house Pvt ltd  1994 
 - 169p. 
<br/><br/><label>ISBN: </label>0-7069-8065-4 
<br/><br/><label>Dewey Class. No.: </label>507.6