Di Benedetto, Paolo, Giuseppe Niccoli, Alessandro Beltrame, Renato Gisonni, Vanni Cainero, and Araldo Causero. 2016. “Histopathological Aspects and Staging Systems in Non-Traumatic Femoral Head Osteonecrosis: An Overview of the Literature”. Acta Biomedica Atenei Parmensis 87 (1 -S): 15-24. https://mattioli1885journals.com/index.php/actabiomedica/article/view/5345.