Das, P. N. <br/><br/>
Introduction to Manual Telephony  

 - CALCUTTA  Modern Book Agency  1978 
 - p.150 
<br/><br/><label>Subjects--Topical Terms: </label><br/>MANUAL TELEPHONE WORKING<br/>JUNCTION AND TRUNK WORKING
<br/><br/><label>Dewey Class. No.: </label>621.385 D229