@ARTICLE {2107,
author={D. Graça and J. F. Costa},
doi={10.1016/S0885-064X(03)00034-7},
journal={Journal of Complexity},
title={Analog computers and recursive functions over the reals},
year={2003},
month={January},
volume={19},
number={5},
pages={644-664},
ISSN={0885-064X}
}