CCITT, ITTCC <br/><br/>
RED BOOK,VOL.III,FASCICLE III.5: INTEGRATED SERVICES DIGITAL NETWORK (CCITT STANDARD) 

 - 1 
 - GENEVA  ITU  1985 
 -  139 
<br/><br/><label>ISBN: </label>NCST 
<br/><br/><label>Dewey Class. No.: </label>335