The work of IAU Commission 31 is contained in the following sections contributed by the Members.The two Working Groups installed during the period 1984-1987 :
“The Use of Millisecond Pulsars and Timing of Pulsars”
and
“Time Transfer with Modern Techniques”,
chaired by D. ALLAN and H. FLIEGEL respectively, maintained their activities and will report at the General Assembly. Time transfer with GPS has been and is still of concern with the introduction of the Selective Availability (SA), but the adaptation of the common view method seems to overcome part of this difficulty (Fliegel et al., 1990).