1. Department of Agricultural Economics, School of Agriculture, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
2. Department of Regional and Cross Border Development, University of Western Macedonia, 50100 Kozani, Greece
3. Department of Forestry and Management of the Environment and Natural Resources, Faculty of Agricultural and Forestry Sciences, Democritus University of Thrace, 68200 Orestiada, Greece