1. Department of Business Administration, University of Western Macedonia, 51100 Grevena, Greece
2. Department of Agriculture, School of Agricultural Sciences, University of Western Macedonia, 53100 Florina, Greece
3. Department of Forestry and Natural Environment, School of Agriculture Forestry and Natural Environment, Aristotle University of Thessaloniki, 54134 Thessaloniki, Greece
4. Department of Management Science and Technology, University of Western Macedonia, 50100 Kozani, Greece