1. University Institute of Technology, University of NgaoundéréNgaoundéréCameroon
2. Department of MathematicsTexas A&M University-Central TexasKilleenUSA
3. Laboratoire Électronique, Informatique et ImageUniversité Bourgogne-Franche-ComtéDijonFrance
4. National Advanced School of Engineering, University of Yaoundé IYaoundéCameroon