JayantM., PuniaR., KaushikR., SharmaR., SachdevA., NadkarniN., and AttriA. “Neuroendocrine Tumors of the Ampulla of Vater: Presentation, Pathology and Prognosis”. JOP. Journal of the Pancreas, Vol. 13, no. 3, May 2012, pp. 263-7, doi:10.6092/1590-8577/626.