KIRKMAN, M. Letter: Caution when using heart rate as a marker of exercise intensity. South African Journal of Sports Medicine, [S. l.], v. 15, n. 3, p. 32–32, 2003. DOI: 10.17159/2078-516X/2003/v15i3a227. Disponível em: https://journals.assaf.org.za/index.php/sajsm/article/view/227. Acesso em: 10 apr. 2025.