B H Wood, J A Bilelough, A Bowron, et al: Incidence and prediction of falls in Parkinson disease: a prospective multidisciplinary study. J Neurol Neurosurg Psychiatry 72: 721-725, 2002.
Goodwin VA, Richards SH, Taylor RS, et al: The effectiveness of exercise interventions for people with Parkinson's disease: a systematic review and meta-analysis. Mov Disord 23(5): 631-640, 2008.