Alomiear, M., and A. Alreshidi. “Teachers’ Characteristics and Their Effect on Students’ Mathematical Achievement in the 4th Grade: A Comparative Study Between Saudi Arabia and the United States of America According to (TIMSS 2019)”. International Journal of Research in Educational Sciences., Vol. 5, no. 1, Dec. 2021, pp. 91 -28, http://iafh.net/index.php/IJRES/article/view/329.