5.	RecommendationsI.440, I.441, I.450, I.451 and I.452



5.1	RecommendationI.440 - ISDN user-network interface data link layer - general aspects (see Rec-
ommendationQ.920, VolumeVI, Fascicle   of the BlueBook)



5.2	RecommendationI.441 - ISDN user-network interface, data link layer specification (see Recom-
mendationG.921, Volume VI, Fascicle   of the BlueBook)



5.3	RecommendationI.450 - ISDN user-network interface layer3 - general aspects (see Recommen-
dationQ.930, VolumeVI, Fascicle  of the BlueBook)



5.4	RecommendationI.451 - ISDN user-network interface layer3 specification for basic call control 
(see RecommendationQ.931, VolumeVI, Fascicle   of the BlueBook)



5.5	RecommendationI.452 - ISDN user-network interface layer3 specification - generic procedures for 
the control of the ISDN supplementary services (see RecommendationQ.932, VolumeVI Fascicle   of 
the Blue Book).