ECORFAN Journal-Democratic Republic of Congo, Volume 5, Number 9, December-2019, is a biannual Journal edited by ECORFAN-Democratic Republic of Congo. Kinshasa 6593 N-31Rép.DémocratiqueduCongo, http://www.ecorfan.org/democraticrepublicofcongo/journal.php, email@example.com. Editor in charge Elisée Ilunga Mbuyamba. ISSN: 2414-4924. Responsible for the last update of this issue ECORFAN Computer Unit. Imelda Escamilla Bouchán, PhD. Vladimir Luna Soto, PhD. Kinshasa 6593 N-31Rép.DémocratiqueduCongo. 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.