G. B. Flugsrud, L. Nordsletten, B. Espehaug, L. I. Havelin, and H. E. Meyer, “The effect of middle-age body weight and physical activity on the risk of early revision hip arthroplasty: A cohort study of 1,535 individuals”, ActaO, vol. 78, no. 1, pp. 99–107, Jan. 2007.