Toftdahl, Karen, et al. “Comparison of Peri- and Intraarticular Analgesia With Femoral Nerve Block After Total Knee Arthroplasty: A Randomized Clinical Trial”. Acta Orthopaedica, vol. 78, no. 2, Jan. 2007, pp. 172-9, doi:10.1080/17453670710013645.