Authors
M. Bourahma
Department of Mathematics, laboratory LAMA, Faculty of Sciences Dhar El Mahraz, Sidi Mohammed Ben Abdallah University, Fez, Morocco
J. Bennouna
Department of Mathematics, Faculty of Sciences Dhar El Mahraz, Sidi Mohammed Ben Abdallah University, Fez, Morocco
M. El Moumni
Department of Mathematics, Faculty of Sciences El Jadida, Chouaib Doukkali University, El Jadida, Morocco