CCITT <br/><br/>
BLUE BOOK,VOLUME III,FASCICLE III.9: INTEGRATED SERVICES DIGITAL NETWORK (ISDN),INTERNETWORK INTERFAC 

 - GENEVA  ITU  1989 
 -  98 
<br/><br/> SC-021 
<br/><br/><label>ISBN: </label>ERNET 
<br/><br/><label>Dewey Class. No.: </label>335