Farid M. Ablayev Aida Gainutdinova On the Lower Bounds for One-Way Quantum Automata. 132-140 http://link.springer.de/link/service/series/0558/bibs/1893/18930132.htm 2000 conf/mfcs/2000 MFCS db/conf/mfcs/mfcs2000.html#AblayevG00