Agarwal, P.; Mital, P.; Meena, V. K.; Mital, P.; Nawal, C. L.; Goyal, L. K. A Comparative Study of Levels of Vitamin B12 in Patients of Type 2 Diabetes Mellitus on Metformin and Not on Metformin at Tertiary Care Center. Int J Adv Med 2016, 3, 759-763.