Havelin, L. I., Fenstad, A. M., Salomonsson, R., Mehnert, F., Furnes, O., Overgaard, S., … Garellick, G. (2009). The Nordic Arthroplasty Register Association. Acta Orthopaedica, 80(4), 393–401. https://doi.org/10.3109/17453670903039544