1. P. Alexandrov, Introduction to set theory and general topology, Moscow, Nauka, 1977 (in Russian).
2. A. Ambainis and R. Freivalds, 1-way quantum finite automata: strengths, weaknesses and generalization, In Proceeding of the 39th IEEE Conference on Foundation of Computer Science, 1998, 332–342. See also quant-ph/9802062 v3
3. A. Brodsky and N. Pippenger, Characterizations of 1-way quantum finite automata, quant-ph/9903014, 1999
4. http://xxx.lanl.gov/archive/quant-ph
. See also its Russian mirror:
http://xxx.itep.ru
.
5. A. Kondacs, J. Watrous, On the power of quantum finite state automata. In Proceeding of the 38th IEEE Conference on Foundation of Computer Science, 1997, 66–75.