NISHAD GABHE, et al. “DIPEPTIDYL PEPTIDASE-4 (DPP-4) INHIBITION: A NOVEL APPROACH FOR THE TREATMENT OF TYPE II DIABETES MELLITUS”. International Journal of Pharma and Bio Sciences, vol. 4, no. 3, Sept. 2013, pp. 629-37, https://ijpbs.net/index.php/journal/article/view/2498.