Joseph, Mary <br/><br/>
Thomas Alva Edison / 
by Mary Joseph 
 - New Delhi:  Learners Press,  1996 
 - p.48 
<br/><br/><label>Subjects--Topical Terms: </label><br/> Physics <br/>Applied Physics
<br/><br/><label>Dewey Class. No.: </label>621.3  / JOS-T