CCITT <br/><br/>
BLUE BOOK,VOLUME VI,FASCICLE VI.10: DIGITAL SUBSCRIBER SIGNALLING SYSTEM NO 1 (DSS1),DATA LINK LAYER 

 - GENEVA  ITU  1989 
 -  141 
<br/><br/> SC-021 
<br/><br/><label>ISBN: </label>ERNET 
<br/><br/><label>Dewey Class. No.: </label>335