Akpan, Itoro Ime, et al. “Effect of Geo-Board and Charts on Students’ Achievement in Mathematics in Essien Udim, Akwa Ibom State, Nigeria”. Journal of Research in Education and Society (JRES) , vol. 14, no. 2, Aug. 2023, pp. 91-102, http://icidr.org.ng/index.php/Jres/article/view/1537.