L. S. Lohmander, L. B. Engesæter, P. Herberts, T. Ingvarsson, U. Lucht, and T. J. S. Puolakka, “Standardized incidence rates of total hip replacement for primary hip osteoarthritis in the 5 Nordic countries: similarities and differences”, ActaO, vol. 77, no. 5, pp. 733–740, Jan. 2006.