J. K. Hofstad, S. B. Winther, T. Rian, O. A. Foss, O. S. Husby, and T. S. Wik, “Perioperative local infiltration anesthesia with ropivacaine has no effect on postoperative pain after total hip arthroplasty”, ActaO, vol. 86, no. 6, pp. 654–658, Nov. 2015.