1. European Commission: Directorate-General for Research and Innovation, Population ageing in Europe. Technical report (2014)
2. Olesen, J., Gustavsson, A., Svensson, M., Wittchen, H.-U., Jonsson, B.: The economic cost of brain disorders in Europe. Eur. J. Neurol. 19, 155–162 (2012)
3. Golbe, L., Mark, M., Sage, J.: Parkinson’s Disease Handbook. American Parkinson Disease Association, Inc., New York (2010)
4. National Parkinson Foundation: Understanding Parkinson’s. Reports (2016)
5. Fishman, P.S.: Paradoxical aspects of parkinsonian tremor. Mov. Disord. 23(2), 168–173 (2008)