ECORFAN Journal Republic of Cameroon, Volume 5, Number 9, December-2019, is a biannual Journal edited by ECORFAN- Republic of Cameroon and the international academy. S / C Zacharie kamaha, Street: Boulevard de la Liberte, Apartamente: Immeuble Kassap, Akwa-Douala. P.C.: 5963, Cameroon, http://www.ecorfan.org/republicofcameroon/, journal@ecorfan.org. Responsible editor: CHIATCHOUA, Cesaire, PhD. ISSN: 2414-4959. Responsible for the last update of this issue ECORFAN Computer Unit. Imelda Escamilla Bouchán, PhD. Vladimir Luna Soto, PhD. S / C Zacharie kamaha, Street: Boulevard de la Liberte, Apartamente: Immeuble Kassap, Akwa-Douala. P.C: 5963, Cameroon. Date of last update December 31, 2019. The opinions expressed by the authors do not necessarily reflect the position of the publisher of the publication. It is strictly forbidden the total or partial reproduction of the contents and images of the publication without prior authorization from the Copyright Office