First experience of the study of prevalence of the Helicobacter pylori-negative peptic ulcer in Lviv Region Journal title: Сучасна гастроентерологія Authors: V. I. Vdovychenko, O. A. Byduk, R. C. Vozny, Y. R. Kurnat, G. B. Miciyra, I. O. Pasichna, M. V. Pynd... Subject(s):