Employment of flexible materials in industrial products and their relationship to variables formal systems. Journal of the College of Basic Education, [S. l.], v. 22, n. 96, p. 431–458, 2022. DOI: 10.35950/cbej.v22i96.8993. Disponível em: https://cbej.uomustansiriyah.edu.iq/index.php/cbej/article/view/8993.. Acesso em: 5 jul. 2024.