Ropivacaine, 0, 1 %, plus sufentanil, 0, 5 microg/ml, versus bupivacaine, 0, 1 %, plus sufentanil, 0, 5 microg/ml, using patient-controlled epidural analgesia for labor: a double-blind comparison. - Fischer,C.; Blanie,P.; Jouen,E.; Vayssiere,C.; Kaloul,I.; Coltat,J.C. (Anesthesiology, 2000)