Damião, C.P., Rodrigues, A.O., Pinheiro, M.F.M.C., Cruz Filho, R.A. da, Cardoso, G.P., Taboada, G.F. and Lima, G.A.B. 2016. Prevalence of vitamin B12 deficiency in type 2 diabetic patients using metformin: a cross-sectional study. São Paulo Medical Journal. 134, 6 (Dec. 2016), 473–479.