Substance use in a comparative perspective : the case of Bulgaria, Czechia, Croatia, Romania and Slovakia / Arnost Vesely, Dagmar Dzurova, editors ; reviewers, PhDr. Ladislav Csemy, MUDr. Darina Sedlakova, MPH. ; foreword by Prof. Richard Scheffler, Prof. Martin Potucek ; cover design and layout Jan Serych.