Clinical experience of use of 13C-breath tests in oesophagogastroduodenal diseases: selective questions - Shypulin, Vadim; Chernyavskyi, Volodimir; Nechypurenko, Tetyana; Neverovskyi, Artyom; Gvozdecka, Lesya; Mikhn’ova, Natallya (Gastroenterology Review/Przegląd Gastroenterologiczny, 2020)