Affiliation: | aSchool of Management Science and Engineering, Nanjing University, Nanjing 210093, PR China;bIbn Zohr University, ENSA, BP 32/S, Agadir, Morocco;cMathematics Department, COMSATS Institute of Information Technology, Sector-H-8/1, Islamabad 44000, Pakistan;dIbn Zohr University, Présidence, BP 32/S, Agadir, Morocco |