Kessler, Gary C   Southwick, Peter V <br/><br/>
ISDN  Concepts, Facilities, and Services 

 - New York  McGraw-Hill  1997 
 - 24X16 
<br/><br/><label>ISBN: </label>0070342490 
<br/><br/><label>Dewey Class. No.: </label>621.382 K42