Biswas, Nripendra N. <br/><br/>
Principles of telephony 
/Nripendra N.Biswas 
 - Bangalore  Radiant Books  1996 
 - vii, 138 p. 
<br/><br/>  Includes index. 
<br/><br/><label>ISBN: </label>818527309X 
<br/><br/><label>Dewey Class. No.: </label>621.385  / BIS