1. Gallagher JC, Melton LJ, Riggs BL, Bergstrath E. Epidemiology of fractures of the proximal femur in Rochester, Minnesota. Clin Orthop 1980;150:163?171.
2. Lewinnek GE, Kelsey J, White III AA, Kreiger NJ. The significance and a comparative analysis of the epidemiology of hip fractures. Clin Orthop 1980; 152:35?43.
3. Pogrund H, Makin M, Robin G, Menczel J, Steinberg R. The epidemiology of femoral neck fractures in Jerusalem: A prospective study (1967?1971). Clin Orthop 1977;122:141?146.
4. Chalmers J, Ho KC. Geographical variations in senile osteoporosis: The association with physical activity. J Bone Joint Surg 1970;52B:667?675.
5. Solomon L. Osteoporosis and fracture of the femoral neck in the South African Bantu. J Bone Joint Surg 1968;50B:2?13.