SONG, H.; XUE, H. The Impact of Extracurricular Tutoring Time Investment on Academic Performance of Secondary School Students: An Empirical Analysis Based on PISA2015 Data of Four Provincial Administrative Regions in China. Science Insights Education Frontiers, [S. l.], v. 11, n. 2, p. 1551–1565, 2022. DOI: 10.15354/sief.22.or052. Disponível em: https://www.bonoi.org/index.php/sief/article/view/721. Acesso em: 18 apr. 2026.