Vega, F. J.; García-Barrera, P.; Perrilliat, M. del C.; Coutiño, M. A.; Mariño-Pérez, R. El Espinal, a New Plattenkalk Facies Locality from the Lower Cretaceous Sierra Madre Formation, Chiapas, Southeastern Mexico. revmexcg 2018, 23, 323-333.