Hoefnagels, E. M., Obradov, M., Reijnierse, M., Anderson, P. G., & Swierstra, B. A. (2007). Sonography after total hip replacement: Reproducibility and normal values in 47 clinically uncomplicated cases. Acta Orthopaedica, 78(1), 81–85. https://doi.org/10.1080/17453670610013457