Migliore, A.; Tormenta, S.; Valente, C.; Massafra, U.; Martin Martin, L.; Carmenini, E.; Bernardini, A.; Alimonti, A. Intra-Articulaar Treatment With Hylan G-F 20 under Ultrasound Guidance in Hip Osteoarthritis. Clinical Results After 12 Months Follow-up. Reumatismo 2005, 57, 36-43.