DIRECT CONNECTION ON THE MOVE: CHARACTERIZATION OF USER MOBILITY IN CELLULAR-ASSISTED D2D SYSTEMS СтатьяOrsino A., Moltchanov D., Gapeyenko M., Samuylov A., Andreev S., Militano L., Araniti G., Koucheryavy Y.IEEE Vehicular Technology Magazine. Том Vol 11 Issue 3. 2016. С. 38-48