Hooff, M. L. van, W. C. H. Jacobs, P. C. Willems, M. W. J. M. Wouters, M. de Kleuver, W. C. Peul, R. W. J. G. Ostelo, and P. Fritzell. “Evidence and Practice in Spine Registries”. Acta Orthopaedica, vol. 86, no. 5, Sept. 2015, pp. 534-4, doi:10.3109/17453674.2015.1043174.