Das, P. N.  <br/><br/>
Line telegraphy 
P. N. Das 
 - Calcutta  Modern Book Agency Private Ltd.  1962 
 - vi, 179p. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Telegraph<br/>Telegraph line
<br/><br/><label>Dewey Class. No.: </label>621.383 D2601l