Automatic extraction of knowledge for diagnosing COVID-19 disease based on text mining techniques: A systematic review. Periodicals of Engineering and Natural Sciences, [S. l.], v. 9, n. 2, p. 918–929, 2021. DOI: 10.21533/pen.v9.i2.795. Disponível em: https://pen.ius.edu.ba/index.php/pen/article/view/795. Acesso em: 25 jul. 2026.