The ITU-T specs are the best.
Here the numbers of specs which describes SS7.
Message transfer part Q.701–Q.709
Simplified message transfer part Q.710
Signalling connection control part Q.711–Q.719
Telephone user part Q.720–Q.729
ISDN supplementary services Q.730–Q.739
Data user part Q.740–Q.749
Signalling System No. 7 management Q.750–Q.759
ISDN user part Q.760–Q.769
Transaction capabilities application part Q.770–Q.779
Test specification Q.780–Q.799