Alva Valdivia, Luis M., María Carmen Rosales, Mouloud Benammi, Manuel Grajales Nishimura, Avto Gogitchaichvili, y J. Urrutia Fucugauchi. 2002. «Reconnaissance Microfossil and Magnetic Stratigraphy of the Miocene Sayula-Isla Sequence, Veracruz, Mexico». Geofísica Internacional 41 (2):151-61. https://doi.org/10.22201/igeof.00167169p.2002.41.2.283.