AALI J. MOHAMMAD, A. ON COLOURING MAPS & SEMIDIRECT PRODUCT GROUPOIDS ON GROUP-POSETS. Journal of Education and Science (JES), [S. l.], v. 19, n. 2, p. 99–109, 2007. DOI: 10.33899/edusj.2007.5790. Disponível em: https://ojs.uomosul.edu.iq/index.php/edusj/article/view/24092. Acesso em: 6 aug. 2025.