[en] Production of dielectron pairs is studied within a Quark-Gluon String Model for hadron-nucleus and nucleus-nucleus collisions. The energy range from a few GeV/nucleon up to a few hundred GeV/nucleon is covered and available experimental data are analyzed. Contributions of different hadronic sources of dilepton production as well as the influence of an experimental acceptance on observable invariant mass spectra are discussed. A special attention is paid to the study of angular characteristics of e⁺e^- pairs created in heavy ion collisions. The proposed study of the decay dilepton anisotropy seems to be hopeful for disentangling different sources or different models. (orig.)