Abatangelo, G., L. Ferroni, E. Bressan, C. Gardin, P. Pinton, R. Cortivo, S. Sivolella, and B. Zavan. “Stemness Ability of Human Dental Pulp Stem Cells Related to the in Vivo and in Vitro Aging”. Italian Journal of Anatomy and Embryology, vol. 116, no. 2, Nov. 2011, p. 8, https://oajournals.fupress.net/index.php/ijae/article/view/4581.