BELZER, J. Punched Card System. Journal of Information and Knowledge, [S. l.], v. 2, n. 1, p. 69–77, 2000. DOI: 10.17821/srels/1965/v2i1/49123. Disponível em: https://srels.org/index.php/sjim/article/view/49123. Acesso em: 10 jan. 2025.