Juraj Hromkovic Martin Sauerhoff The Power of Nondeterminism and Randomness for Oblivious Branching Programs. 159-182 2003 36 Theory Comput. Syst. 2 http://dx.doi.org/10.1007/s00224-002-1050-x db/journals/mst/mst36.html#HromkovicS03