van Benthem, S. A. C. ., R. W. . Valenzuela, and G. J. . Ponce. “Measurements of Upper Mantle Shear Wave Anisotropy from a Permanent Network in Southern Mexico”. Geofisica Internacional, vol. 52, no. 4, Oct. 2013, pp. 385-02, doi:10.22201/igeof.00167169p.2013.52.4.427.