Flores-Márquez, E.L. Ramírez-Rojas, A. Perez-Oregon, J. Sarlis, N.V. Skordas, E.S. Varotsos, P.A., Natural time analysis of seismicity within the mexican flat slab before the M7.1 earthquake on 19 september 2017, Entropy, (22), 2020, MDPI AG, 1099-4300