Interworking with satellite mobile systems : recommendations Q.1100 - Q.1152 / International Telecommunication Union
Specifications of signalling systems Nos. 4 and 5 : recommendations Q.120 - Q.180 / International Telecommunication Union
Specifications of signalling systems R1 and R2 : recommendations Q.310 - Q.490 / International Telecommunication Union
Digital local, transit, combined and international exchanges in integrated digital networks and mixed analogue-digital networks : supplements: recommendations Q.500-Q.554 / International Telecommunication Union