1. Department of Medicine and Surgery, University of Parma, 43124 Parma, Italy
2. Cardiac Surgery Clinic, University Hospital of Parma, Via Gramsci 14, 43125 Parma, Italy
3. Cardiology Unit, University Hospital of Parma, Via Gramsci 14, 43125 Parma, Italy
4. Cardiac Surgery Department, Hospital Universitario Central de Asturias, 33004 Oviedo, Spain
5. Cardiac Surgery Unit, San Giovanni Bosco Hospital, 10144 Turin, Italy
6. Department of Cardiothoracic Surgery, Erasmus University Medical Center, 3062 Rotterdam, The Netherlands
7. Division of Cardiac Surgery, Department of Critical Care Medicine, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB 11220, Canada
8. Medical Library, University of Parma, 43124 Parma, Italy
9. Cardiovascular Research Institute Maastricht (CARIM), 6200 Maastricht, The Netherlands