Rosengren, B. E., H. G. Ahlborg, P. Gärdsell, I. Sernbo, R. M. Daly, J.- Åke Nilsson, and M. K. Karlsson. “Bone Mineral Density and Incidence of Hip Fracture in Swedish Urban and Rural Women 1987–2002”. Acta Orthopaedica, vol. 81, no. 4, Aug. 2010, pp. 453-9, doi:10.3109/17453674.2010.492762.