A STRUCTURAL APPROACH FOR PDF DOCUMENTS CLASSIFICATION. International Journal of Advance Engineering and Research Development (IJAERD), [S. l.], v. 4, n. 4, p. 851–858, 2017. Disponível em: https://www.ijaerd.org/index.php/IJAERD/article/view/2683. Acesso em: 8 sep. 2025.