Akpabio, E., U. S. Ekong, T. O. Uwah, E. D. . Ekpa, P. M. E. Ubulom, G. E. Jacobs, and M. E. Fred. “Formulation and Evaluation of Theophylline Sustained Release Tablet Using Lasianthera Africana Gum”. Nigerian Journal of Pharmaceutical and Applied Science Research, vol. 5, no. 2, Aug. 2020, pp. 41-48, http://mail.nijophasr.net/index.php/nijophasr/article/view/125.