A. M. Childs, Farhi, E., and Gutmann, S.,
“An example of the difference between quantum and classical random walks”,
Quantum Information Processing, vol. 1, no. 1/2, pp. 35 - 43, 2001.
A. M. Childs, Kothari, R., Ozols, M., and Roetteler, M.,
“Easy and hard functions for the Boolean hidden shift problem”,
Proceedings of TQC 2013, vol. 22, pp. 50-79, 2013.