Gomes, Lúcia, et al. “Niveles De Actividad física De Adolescentes Portugueses En El Primer Periodo De Confinamiento Por La Pandemia De COVID-19 Y Las Primeras Actividades De Profesores Y Entrenadores: Un Estudio transversal(Physical Activity Levels of Portuguese Adolescents in the First Period of Confinement Due to the COVID-19 Pandemic and the First Activities of Teachers and Coaches: A Cross-Sectional Study)”. Retos, vol. 47, Jan. 2023, pp. 701-9, https://doi.org/10.47197/retos.v47.93923.