[1] Univ Tehran, Res Inst Energy Management & Planning, Tehran 1417466191, Iran
[2] Webster Vienna Private Univ, Dept Business & Management, A-1020 Vienna, Austria
[3] St Anselm Coll, Dept Econ & Business, Manchester, NH 03102 USA
[4] Ionian Univ, Fac Econ Sci, Dept Tourism, Kalypso Bldg,4 P Vraila Armeni, Corfu 49100, Greece