Espehaug, B. (1999) “The effect of hospital-type and operating volume on the survival of hip replacements: A review of 39,505 primary total hip replacements reported to the Norwegian Arthroplasty Register, 1988-1996”, Acta Orthopaedica, 70(1), pp. 12–18. doi: 10.3109/17453679909000949.