Hoikka, V. et al. 1991. Intertrochanteric varus osteotomy for Perthes’ disease: Radiographic changes after 2–16-year follow-up of 126 hips. Acta Orthopaedica. 62, 6 (Jan. 1991), 549–553. DOI:https://doi.org/10.3109/17453679108994494.