Ramazzina, I., F. Pogliacomi, S. Bertuletti, and C. Costantino. “Long Term Effect of Selective Muscle Strengthening in Athletes With Patellofemoral Pain Syndrome”. Acta Bio Medica Atenei Parmensis, Vol. 87, no. 1 -S, Apr. 2016, pp. 60-68, https://www.mattioli1885journals.com/index.php/actabiomedica/article/view/5351.