@ARTICLE {7266,
author={P. Mateus and D. Qiu Qiu and L. Li},
doi={10.1016/j.ic.2012.07.002},
journal={Information and Computation},
title={On the complexity of minimizing probabilistic and quantum automata},
year={2012},
month={March},
volume={218},
number={1},
pages={36-53},
ISSN={0890-5401}
}