Abdelkader Aguir Faculty of Economics and Management of Sousse, Lab MOFID / Lab ESPI2R (Groupe ESPI)   3 rue boris vian App18 SAINT-MARTIN-D'HÈRES, France 38400 France   aguir_a@yahoo.fr             JEL Areas: E5 : Monetary Policy, Central Banking, and the Supply of Money and Credit: General E6 : Macroeconomic Policy, Macroeconomic Aspects of Public Finance, and General