Authors: Verheyden, Geert Kampshoff, Caroline S. Burnett, Malcolm E. et al.
Source: Physical Therapy. Feb2014, Vol. 94 Issue 2, p230-239.
Authors: Stack, Emma L. Roberts, Helen C.
Source: Parkinson's Disease (20420080). 2013, p1-8. 8p. 4 Charts, 2 Graphs.