Ertem, Deniz, et al. “Helicobacter Pylori Infection in Turkish Preschool and School Children: Role of Socioeconomic Factors and Breast Feeding”. The Turkish Journal of Pediatrics, vol. 45, no. 2, Apr. 2003, pp. 114-22, https://doi.org/10.24953/turkjpediatr.2003.2871.