J. E. Okon and G. U. Egesie, “Gastrin, Histamine Prostaglandin: Indicators for assessing efficacy of cimetidine, Omeprazole and Ranitidine in Gastric Ulcer Treatment”, Janaki Med. Coll. J. Med. Sci., vol. 5, no. 2, pp. 5–12, Jan. 2018.