Guralnik JM, Ferrucci L, Simonsick EM, Salive ME, Wallace RB : Lower-extremity function in persons over the age of 70 years as a predictor of subsequent disability.
Guralnik J.M., Ferrucci L., Simonsick E.M., Salive M.E., Wallace R.B.: Lower-extremity function in persons over the age of 70 years as a predictor of subsequent disability.