رأفت خالد م. The Effective Date Representation for MultiVariation Maps. College of Basic Education Research Journal, [S. l.], v. 4, n. 2, p. 168–187, 2007. Disponível em: https://stats.uomosul.edu.iq/index.php/berj/article/view/38689. Acesso em: 26 oct. 2025.