Castriconi, R., A. Dondero, F. Pastorino, M. Della Chiesa, M. Corrias, F. Morandi, V. Pistoia, D. Olive, F. Bellora, F. Locatelli, A. Castellano, L. Moretta, C. Bottino, and A. Moretta. “PD-L1 Expression in Metastatic Neuroblastoma As an Additional Mechanism for Limiting Immune Surveillance”. Italian Journal of Anatomy and Embryology, vol. 120, no. 1, Sept. 2015, p. 26, https://oajournals.fupress.net/index.php/ijae/article/view/3980.