Misawa-Matsushima, T., B. Salvatierra-Izaba, and A. Nazar-Beutelspacher. “Fertility, Migration and Environment in Indigenous Communities in the Sierra Madre of Chiapas, México”. Agricultura, Sociedad Y Desarrollo, vol. 2, no. 2, June 2005, pp. 83-95, https://www.revista-asyd.org/index.php/asyd/article/view/1044.