SarariA. S., FarrajM. A., HamoudiW., and EssawiT. A. “Helicobacter Pylori, a Causative Agent of Vitamin B12 Deficiency”. The Journal of Infection in Developing Countries, Vol. 2, no. 05, Oct. 2008, pp. 346-9, doi:10.3855/jidc.194.