Raimer, Constance, et al. “Continuous Psoas and Sciatic Block After Knee Arthroplasty: Good Effects Compared to Epidural Analgesia or i.v. Opioid Analgesia: A Prospective Study of 63 Patients”. Acta Orthopaedica, vol. 78, no. 2, Jan. 2007, pp. 193-00, doi:10.1080/17453670710013672.