Prabowo, A., S. Sulaiman, and T. Soenyoto. “The Effect of Exercises and Gender on Cardiorespiratory Endurance in the Elderly”. Journal of Physical Education and Sports, Vol. 8, no. 5, Aug. 2019, pp. 105-11, https://journal.unnes.ac.id/sju/jpes/article/view/32528.