Universidad Nacional (Costa Rica). Escuela de Literatura y Ciencias del Lenguaje, Alfaro Jara, O., Barrantes Valverde, M., Chacon Gonzalez, C., Cortez Gonzalez, A., & Jimenez Olivares, Y. (2006). Using authentic readings in the ninth grade in the public school system of Costa Rica, to develop elf classroom activities to enhance students competence. Heredia. C.R.: O. Alfaro J..

Universidad Nacional (Costa Rica). Escuela de Literatura y Ciencias del Lenguaje, Ovidio Alfaro Jara, Marco Barrantes Valverde, Carlos Chacon Gonzalez, Alvaro Cortez Gonzalez, and Yalile Jimenez Olivares. Using Authentic Readings in the Ninth Grade in the Public School System of Costa Rica, to Develop Elf Classroom Activities to Enhance Students Competence. Heredia. C.R.: O. Alfaro J., 2006.

Universidad Nacional (Costa Rica). Escuela de Literatura y Ciencias del Lenguaje, et al. Using Authentic Readings in the Ninth Grade in the Public School System of Costa Rica, to Develop Elf Classroom Activities to Enhance Students Competence. Heredia. C.R.: O. Alfaro J., 2006.