AN EXACT FORM OF SIGNUM FUNCTION. Advances and Applications in Discrete Mathematics, [S. l.], v. 41, n. 4, p. 311–324, 2024. DOI: 10.17654/0974165824022. Disponível em: https://pphmjopenaccess.com/aadm/article/view/1729. Acesso em: 5 jan. 2026.