Alhassane Touré
School of Mathematics and Statistics, Central China Normal University, 152 Luoyu Avenue, Wuhan, Hubei, 430079, P.R. China
Zuo Guoxin
School of Mathematics and Statistics, Central China Normal University, 152 Luoyu Avenue, Wuhan, Hubei, 430079, P.R. China
Tchondo Anakpa Manawessoue
School of Economics, Central China Normal University