CCITT Plenary Assembly (Red Book) Malaga-Torremolinos, 1984 :   Digital Access Signalling System, Recommendations Q.920-Q.931 : Fascicle /   Vol.VI.9 

 - Geneva :   ITU,   1984. 
 - IX, 193 s.;   30 cm. 
<br/><br/><label>ISBN: </label>9261022219