Barbaro, F., et al. “Adult Stem Progenitor Cells of the Rat Thyroid: Side Population Distribution, Intermediate Filament Expression, and Long-Term in Vitro Expansion”. Italian Journal of Anatomy and Embryology, vol. 118, no. 2, Jan. 2014, p. 19, https://oajournals.fupress.net/index.php/ijae/article/view/3407.