Silva, Layse Kelly Costa Tavares da, et al. “K FAMILY: A Relationship Marketing Study of Gym Chain from Paraiba”. Perspectivas Contemporâneas - Contemporary Perspectives, vol. 17, no. 1, Sept. 2022, pp. 1-20, https://periodicos.grupointegrado.br/revista/index.php/perspectivascontemporaneas/article/view/3120.