Roddy, Dennis, Coolen, John <br/><br/>
Electronic communications 

 - 3rd ed. 
 - Delhi  Prentice-Hall of India  1991 
 - xii, 788p, 23cm 
<br/><br/><label>ISBN: </label>0876923961 
<br/><br/><label>Dewey Class. No.: </label>621.380413,  / D, rod