Fibla, J.J., Molins, L., Mier, J.M., et al. (2008) Comparative Analysis of Analgesic Quality in the Postoperative of Thoracotomy: Paravertebral Block with Bupivacaine 0.5% vs. Ropivacaine 0.2%. European Journal of Cardio-Thoracic Surgery, 33, 430-434.