Samperio Sánchez, Nahum. «The Investment of Time in the Study of English: A Little Considered Factor». Ciencia Latina Revista Científica Multidisciplinar 7, no. 2 (mayo 23, 2023): 8483-8505. Accedido septiembre 24, 2025. https://ciencialatina.org/index.php/cienciala/article/view/5970.