TOMPKINS, Trevor; HANDLEY, Dan. Giving e-mail back to the users: Using digital signatures to solve the spam problem. First Monday, [S. l.], v. 8, n. 9, 2003. DOI: 10.5210/fm.v8i9.1074. Disponível em: https://firstmonday.org/ojs/index.php/fm/article/view/1074. Acesso em: 19 mar. 2024.