1. Peoples' Friendship University of Russia, Faculty of Economics, Department of Regional Economics and Geography, Moscow, Russian Federation + Institute for Demographic Research of the Federal Research Sociological Center, Russian Academy of Sciences, Moscow, Russian Federation
2. Peoples' Friendship University of Russia, Faculty of Economics, Department of Regional Economics and Geography, Moscow, Russian Federation
3. Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
4. Geographical Institute “Jovan Cvijić” SASA, Belgrade, Serbia