[1] Democritus Univ Thrace, Dept Environm Engn, Business & Environm Technol Econ Lab, Vas Sofias 12, Xanthi, Greece
[2] Hellen Open Univ, Patras, Greece
[3] Yunnan Univ Finance & Econ, Kunming, Yunnan, Peoples R China
[4] Charles Sturt Univ, Sch Management & Mkt, Wagga Wagga, NSW 2678, Australia
[5] Univ Aegean, Dept Environm, Univ Hill, Mitilini, Greece