Bravo, L. E., Realpe, J. L., Portilla, H., Parra, A. E. and Valenzuela, N. (1989) “Environmental duodenitis and gastritis, distribution of Campylobacter piloris and relationship with intragastric pH and nitrite”, Colombia Medica, 20(4), pp. 135–141. doi: 10.25100/cm.v20i4.6268.