Jacobsen, Steffen, et al. “Radiographic Case Definitions and Prevalence of Osteoarthrosis of the HipA Survey of 4 151 Subjects in the Osteoarthritis Substudy of the Copenhagen City Heart Study”. Acta Orthopaedica, vol. 75, no. 6, Jan. 2004, pp. 713-20, doi:10.1080/00016470410004085.