جعفر د/ إقبال محمد احمد. The availability of twenty-first century skills in Yemeni science books for the fifth grade of basic education. Humanities and Educational Sciences Journal, [S. l.], v. 8, n. 20, p. 149–173, 2022. DOI: 10.55074/hesj.v8i20.389. Disponível em: https://hesj.org/ojs/index.php/hesj/article/view/389. Acesso em: 9 nov. 2026.