First Author:   Komivi Afawubo CEREFIGE –Univ. of Lorraine and CRESE EA3190-Univ. of Bourgogne Franche-Comté komivi.afawubo@univ-lorraine.fr   13 Rue Michel Ney NANCY, 54000, FRANCE       Second Author: Mawuli kodjovi Couchoro CERFEG-University of Lomé, Togo couchoro@hotmail.com   Lomé, PO Box 7660, Togo