ITU-T E.422-1996
关于国际去话呼叫的服务质量监视 电话网络和综合业务服务网(ISDN)服务质量,网络管理和通信工程
Observations on International Outgoing Telephone Calls for Quality of Service - Telephone Network and ISDN Quality of Service Network Management and Traffic Engineering (Study Group 2) 18 pp