Hayat, Waqar, et al. “VITAMIN B12 DEFICIENCY IN TYPE II DIABETIC PATIENTS ON METFORMIN THERAPY;A STUDY CONDUCTED IN TERTIARY CARE HOSPITAL OF PESHAWAR”. Journal of Medical Sciences, vol. 26, no. 2, June 2018, pp. 151-4, https://jmedsci.com/Jmedsci/article/view/543.