Lugo-Hubp, José, et al. “Mass Movement Processes in the Sierra Norte De Puebla, October 1999: Cause and Effects”. Revista Mexicana De Ciencias Geológicas, vol. 22, no. 2, Apr. 2018, pp. 212-28, https://rmcg.unam.mx/index.php/rmcg/article/view/855.