Mariani, G. A., R. Agushi, A. Balduzzi, M. Zoli, L. Maroni, M. C. Mazzotti, C. Panzavolta, A. M. Billi, L. Cocco, and L. Manzoli. “The Circle of Willis: A Review and a Case Report”. Italian Journal of Anatomy and Embryology, vol. 118, no. 2, Jan. 2014, p. 131, https://oajournals.fupress.net/index.php/ijae/article/view/3784.