Biswas, N. N., Au. <br/><br/>
Principles of telephony 

 - Bombay  Asia Publication House  1974 
<br/><br/><label>ISBN: </label>021022312X 
<br/><br/><label>Subjects--Uniform Titles: </label><br/>Technology
<br/><br/><label>Dewey Class. No.: </label> /