MAKSYMCHUK, D., MAMCHYCH, V. and MAKSYMCHUK, V. Surgical treatment of complicated duodenal ulcers with different variants of their localization. Journal of Education, Health and Sport. Online. 30 September 2021. Vol. 11, no. 9, pp. 773-780. [Accessed 27 July 2024]. DOI 10.12775/JEHS.2021.11.09.093.