GOPINATH, M. A. Fountain Pen Production: Depth Classification Version of CC. Journal of Information and Knowledge, [S. l.], v. 9, n. 3, p. 336–352, 1972. DOI: 10.17821/srels/1972/v9i3/49237. Disponível em: https://srels.org/index.php/sjim/article/view/49237. Acesso em: 9 jan. 2025.