Nascimento, C. M. C., S. Gobbi, M. S. Hirayama, and M. C. Brazão. “Level of Physical Activity and Main Barriers Perceived by Older People Living in Rio Claro”. Journal of Physical Education , Vol. 19, no. 1, July 2008, pp. 109-18, https://periodicos.uem.br/ojs/index.php/RevEducFis/article/view/4321.