1. Departement of mathematics, Faculty of applied Sciences, University Ibn Zohr, 86153 Aït-Melloul, Morocco
2. Department of Ecology and Biology, Tuscia University, Largo dell'Università, 01100 Viterbo, Italy
3. Moulay Ismail University of Meknes, FST Errachidia, MAIS Laboratory, MAMCS Group, P.O. Box 509, Boutalamine 52000, Errachidia, Morocco