Testing the random walk hypothesis of stock indexes through varianceratio . Periodicals of Engineering and Natural Sciences, [S. l.], v. 7, n. 1, 2019. DOI: 10.21533/pen.v7.i1.1462. Disponível em: https://pen.ius.edu.ba/index.php/pen/article/view/1462. Acesso em: 15 jun. 2026.