by Sorin Istrail
Reference:
Sorin Istrail, "An arithmetical hierarchy in propositional dynamic logic", In Information and Computation, vol. 81, no. 3, pp. 280-289, 1989.
Bibtex Entry:
@ARTICLE{Istrail1989,
author = {Istrail, Sorin},
title = {An arithmetical hierarchy in propositional dynamic logic},
journal = {Information and Computation},
year = {1989},
volume = {81},
pages = {280--289},
number = {3},
owner = {Derek},
timestamp = {2012.05.08},
url = {http://www.brown.edu/Research/Istrail_Lab/papers/an arithmetical hierarchy in propositional dynamic logic.pdf},
category = {Theory of Computation}
}