1. School of Mathematics and Information Science, Guangzhou University, Guangzhou 510006, China
2. Laboratory LAMA, Faculty of Sciences Dhar El Mahraz, Sidi Mohamed Ben Abdellah University, B.P. 1796 Fès-Atlas, Fez 30000, Morocco
3. LISTI, National School of Applied Sciences of Agadir, Ibn Zohr University, Agadir 80000, Morocco