Institution: | 1. Department of Mathematics, Faculty of Sciences and Technology, P. O. Box 416, Tangier, Morocco;2. Department of Mathematics, FPL, University Abdelmalek Essaadi, B.P 745, Larache, Morocco;1. Institut Jean Le Rond d’Alembert, Sorbonne Universities, UPMC Univ Paris 06, CNRS, UMR 7190, 75005 Paris, France;2. Dipartimento di Ingegneria Strutturale e Geotecnica, Univ. di Roma La Sapienza, Via Eudossiana 18, 00184 Rome, Italy |