Zhakun, I.B., Sorokopud, O.O., Strilchuk, L.M., Kit, Z.M. and Kondratyuk, M.O. 2017. Diagnostic value of blood urea and bilirubin levels determination in patients with gastroduodenal zone diseases. Zaporozhye Medical Journal. 6 (Nov. 2017). DOI:https://doi.org/10.14739/2310-1210.2017.6.114717.