L. Nand, S. Mahto, D. K. Garg, and B. Kumar, “Vitamin B12 deficiency in patients of type 2 diabetes mellitus treated with metformin: a cross section observational study from a tertiary care centre in Sub-Himalayan region of North India”, Int J Res Med Sci, vol. 8, no. 4, pp. 1248–1253, Mar. 2020.