de Oliveira, G., D. A. Santos Silva, R. Mengue Maggi, E. L. Petroski, and J. M. de Farias. “Sociodemographic Factors and Physical Fitness Associated With Low Levels of Physical Activity in Adolescents in Southern Brazil”. Journal of Physical Education , Vol. 23, no. 4, Jan. 2013, pp. 635-4, https://periodicos.uem.br/ojs/index.php/RevEducFis/article/view/17510.