First Author:   Jean-michel Sahut Amiens School of Management and CEREGE EA 1722 University of Poitiers jmsahut@gmail.com   18 place Saint Michel Amiens, 80260, France   +33 6 33 42 00 99(Phone) +33 6 33 42 00 99(Fax) Second Author: Medhi Mili University of Poitiers & University of Sfax Mehdi.Mili@isgs.rnu.tn