Bertuzzi, R. C. de M., E. Rumenig-Souza, E. Franchini, F. Y. Nakamura, K. A. Matsushigue, and M. A. P. D. Kiss. “Heart Rate and Rating of Perceived Exertion Responses During Exercise Performed at Intensities Relative to Anaerobic Threshold”. Journal of Physical Education , Vol. 19, no. 3, Dec. 2008, pp. 437-43, https://periodicos.uem.br/ojs/index.php/RevEducFis/article/view/6002.