Postage Stamps and Digital Philately of Europe Countries . Library Progress (International), [S. l.], v. 40, n. 1, p. 12–20, 2020. DOI: 10.48165/. Disponível em: https://journals.acspublisher.com/index.php/lp/article/view/9131. Acesso em: 14 mar. 2025.