Márquez -Barquero, M., C. Azofeifa-Mora, and D. Rodríguez- Méndez. “Comparison of the Attitudes of Adolescents According to Sex and School Level towards Physical Education”. Innovaciones Educativas, vol. 21, no. 30, June 2019, pp. 13-24, doi:10.22458/ie.v21i30.2479.