Giorgio Derchi, Manuela Balocco, Patrizio Bina, Vincenzo Caruso, Domenico G D’Ascola, Roberto Littera, Raffaella Origa, Maria D. Cappellini and Gian L. Forni (2014) “Efficacy and safety of sildenafil for the treatment of severe pulmonary hypertension in patients with hemoglobinopathies: results from a long-term follow up”, Haematologica. Pavia, Italy, 99(2), pp. e17-e18. doi: 10.3324/haematol.2013.095810.