BELZER, J. Symbol Manipulation. Journal of Information and Knowledge, [S. l.], v. 2, n. 2, p. 161–173, 2000. DOI: 10.17821/srels/1965/v2i2/49133. Disponível em: https://srels.org/index.php/sjim/article/view/49133. Acesso em: 18 apr. 2025.