Cristalli, M.P., R. Marini, G. La Monaca, D. Vitolo, G. Pompa, and S. Annibali. 2013. “Double Localization of Keratoacanthoma on the Cutaneous and Mucosal Sides of the Lower Lip: Report of a Case”. Oral & Implantology 6 (4):94-98. https://www.oimplantology.org/oimp/article/view/106.