@article{ref1,
title="Maintaining two voluntary motor activities at the same time; normal values and its impairment in Parkinson's disease",
journal="Transactions of the American Neurological Association",
year="1954",
author="Schwab, R. S. and Chafetz, M. E. and Walker, S.",
volume="13",
number="79th Meeting",
pages="216-220",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0065-9479",
doi="",
url="http://dx.doi.org/"
}