Assaad Ghazouani LVPNC, FSJEGJ, university of jendouba   FSJEGJ BP 277, Essanabel, 8122, Jendouba, Tunisie Jendouba, 8100 Tunisie   assaad.ghazouani@fsjegj.rnu.tn             JEL Areas: C5 : Econometric Modeling: General Q5 : Environmental Economics: General