Mustafa GÜLŞEN, et al. “Gastric Juice Ascorbic Acid Concentrations in Helicobacter Pylori (+) and (-) Patients”. Turkish Journal of Gastroenterology, vol. 6, no. 1, Apr. 2020, pp. 102-4, https://tjg.avesjournals.com/index.php/tjg/article/view/1076.