Huhnstock, Stefan, Svein Svenningsen, Are H Pripp, Terje Terjesen, and Ola Wiig. 2014. “The Acetabulum in Perthes’ Disease: Inter-Observer Agreement and Reliability of Radiographic Measurements”. Acta Orthopaedica 85 (5):506-12. https://doi.org/10.3109/17453674.2014.934188.