Testing the random walk hypothesis of stock indexes through variance-ratio . Periodicals of Engineering and Natural Sciences, [S. l.], v. 7, n. 1, 2019. DOI: 10.21533/pen.v7.i1.1481. Disponível em: https://pen.ius.edu.ba/index.php/pen/article/view/1481. Acesso em: 14 jul. 2026.