Jamil, Zubia, et al. “CREATININE CLEARANCE AS EFFECTIVE NON-INVASIVE MARKER IN DETERMINING GASTROINTESTINAL LESIONS AND HELICOBACTER PYLORI INFECTION: Non-Invasive Marker in Helicobacter Pylori Infection”. Pakistan Armed Forces Medical Journal, vol. 68, no. 5, Oct. 2018, pp. 1161-67, https://pafmj.org/PAFMJ/article/view/2283.