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Moore, SJ; Warren, MJ (1 June 2012). “The anaerobic biosynthesis of vitamin B12.”. Biochemical Society transactions40 (3): 581–6. doi:10.1042/BST20120066. PMID22616870.
Gille, D; Schmid, A (February 2015). “Vitamin B12 in meat and dairy products.”. Nutrition reviews73 (2): 106–15. doi:10.1093/nutrit/nuu011. PMID26024497.
Bolaman Z, Kadikoylu G, Yukselen V, Yavasoglu I, Barutca S, Senturk T (2003). “Oral versus intramuscular cobalamin treatment in megaloblastic anemia: a single-center, prospective, randomized, open-label study”. Clin Ther25 (12): 3124-34. doi:10.1016/S0149-2918(03)90096-8. PMID14749150.
Lane LA, Rojas-Fernandez C (2002). “Treatment of vitamin b(12)-deficiency anemia: oral versus parenteral therapy”. Ann Pharmacother36 (7-8): 1268-72. doi:10.1345/aph.1A122. PMID12086562.
Butler CC et al. (2006). “Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency: a systematic review of randomized controlled trials”. Fam Pract23 (3): 279-85. doi:10.1093/fampra/cml008. PMID16585128.
“Cancer incidence and mortality after treatment with folic acid and vitamin B12”. Journal of the American Medical Association302 (19). (2009). doi:10.1001/jama.2009.1622. PMID19920236.
“Long-Term, Supplemental, One-Carbon Metabolism–Related Vitamin B Use in Relation to Lung Cancer Risk in the Vitamins and Lifestyle (VITAL) Cohort”. Journal of Clinical Oncology35 (30). (2017). doi:10.1200/JCO.2017.72.7735. PMID28829668.