Liddicoat, J. et al. 1981. Paleomagnetic investigation of quaternary sediment at Tlapacoya, México and at Valsequillo, Puebla, México. Geofísica Internacional. 20, 3 (jul. 1981), 249–262. DOI:https://doi.org/10.22201/igeof.00167169p.1981.20.3.1089.