Rao,Digumarti Bhaskara ed. <br/><br/>
International encyclopaedia of science and tecnology education.vol.9 

 - New Delhi  Discovery pub. house  2000 
 - 334p. 
<br/><br/><label>ISBN: </label>81-7141-548-2 
<br/><br/><label>Dewey Class. No.: </label>620.03     ZRao.P;N9