Dammerer, D., Liebensteiner, M., Kujala, U., Emmanuel, K., Kopf, S., Dirisamer, F., & Giesinger, J. (2018). Validation of the German version of the Kujala score in patients with patellofemoral instability: a prospective multi-centre study. Archives of Orthopaedic and Trauma Surgery. https://doi.org/10.1007/s00402-018-2881-5 (Original work published 2018)