Giannella RA, Broitman SA, Zamcheck N (February 1972). "Competition between bacteria and intrinsic factor for vitamin B 12 : implications for vitamin B 12 malabsorption in intestinal bacterial overgrowth". Gastroenterology. 62 (2): 255–260. doi:10.1016/s0016-5085(72)80177-x. PMID4629318.
Giannella RA, Broitman SA, Zamcheck N (February 1972). "Competition between bacteria and intrinsic factor for vitamin B 12 : implications for vitamin B 12 malabsorption in intestinal bacterial overgrowth". Gastroenterology. 62 (2): 255–260. doi:10.1016/s0016-5085(72)80177-x. PMID4629318.