Pantzar-Castilla, E. H. S. ., P. Wretenberg, and J. Riad. “Knee Flexion Contracture Impacts Functional Mobility in Children With Cerebral Palsy With Various Degree of Involvement: A Cross-Sectional Register Study of 2,838 Individuals”. Acta Orthopaedica, vol. 92, no. 4, June 2021, p. 500, doi:10.1080/17453674.2021.1934801.