Serrano Romero, E. C. “Natural Approach or Cognitive Approach. Learning or Acquiring a Foreign Language? Research Study at Centro De Lenguas De La Universidad Autónoma De Ciudad Juárez”. HUMAN REVIEW. International Humanities Review / Revista Internacional De Humanidades, vol. 1, outubro de 2019, p. 49-58, https://www.historicoeagora.net/revHUMAN/article/view/2763.