Unbounded-error quantum computation with small space bounds, A. Yakaryilmaz, A. C. C. Say. Information and Computation, Vol. 209, No. 6, pp. 873-892, 2011. DOI  arXiv


Some preliminary versions:

Languages recognized with unbounded error by quantum finite automata, A. Yakaryilmaz, A. C. C. Say. CSR2009: LNCS Vol. 5675, pp. 356-367, 2009 (Proceedings of the Fourth International Computer Science Symposium in Russia). DOI arXiv

Language recognition by generalized quantum finite automata with unbounded error (poster), A. Yakaryilmaz, A. C. C. Say. TQC2009: (4th Workshop on Theory of Quantum Computation, Communication, and Cryptography), Waterloo, Canada, 2009. arXiv