Ellis, M. E. (2015, November 24). Pemphigoid. Retrieved from http://www.healthline.com/health/bullous-pemphigoid#Overview1
FDA Drug Safety Communication: FDA warns that DPP-4 inhibitors for type 2 diabetes may cause severe joint pain. (n.d.). Retrieved from http://www.fda.gov/Drugs/DrugSafety/ucm459579.htm