CCITT <br/><br/>
BLUE BOOK,VOLUME III,FASCICLE III.7: INTERGRATED SERVICES DIGITAL NETWORK (ISDN) GENERAL STRUCTURE AN 

 - GENEVA  ITU  1989 
 -  352 
<br/><br/> SC-021 
<br/><br/><label>ISBN: </label>ERNET 
<br/><br/><label>Dewey Class. No.: </label>335