[en] The reliability of the identification of a gamma-burst source with a celestial object whose coordinates are given in a star catalogue, depends on the accuracy of the determination of the gamma-burst source coordinates. The accuracy generally is determined by the accuracy of the spacecraft time to UT relation and by the distance between the spacecraft (Mersov and Novak, 1980). The accuracy of the spacecraft time to UT relation must be equal to a few milliseconds. In that case is necessary to take into account the drift of the on-board clock induced by relativity theory effects. (orig./WL)