FREQUANCY OF HELICOBACTER PYLORI IN CASES WITH NONSPESIFIC GASTRITIS IN ERZURUM REGION - OKÇU, N.; ONUK, M. Derya; BURAN, Tahir; AKARSU, Ersin; ÇİFTLİOĞLU, M. Akif (Turkish Journal of Gastroenterology, 1994)