Vanpaemel, Lieve, Paul J M Helders, Wietse Kuis, Hans Pruijs, Jonne Huber, and Willem Keessen. 1994. “Destructive Synovitis in Contralateral Perthes; Disease: A Report of 2 Cases”. Acta Orthopaedica 65 (6):585-88. https://doi.org/10.3109/17453679408994609.