TAWFIQ, L.N.M. Fuzzy Internal Direct Product. Ibn AL-Haitham Journal For Pure and Applied Sciences, Baghdad, Iraq., v. 18, n. 1, p. 80–86, 2019. Disponível em: https://jih.uobaghdad.edu.iq/index.php/j/article/view/2199. Acesso em: 29 mar. 2025.