When forwarding routing changes under a) and b), forms on the model of Tables A or B in Section 2 of the routing document should be used, indicating whether the change is a revision or a new edition. In principle, a complete reprinting of the routing document is desirable from time to time. However, the frequency of production of a revised set of routing information should be left to the discretion of the issuing Administration. It is recommended that a revised set should be brought out not less frequently than once in five years.
ITU-T E.149 SPANISH-1993 Referenced Document
ITU-T E.422 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*， 1996-01-01 Update