HarelR94'

@article{DBLP:journals/iandc/HarelR94,
  author    = {David Harel and
               Danny Raz},
  title     = {Deciding Emptiness for Stack Automata on Infinite Trees},
  journal   = {Inf. Comput.},
  volume    = {113},
  number    = {2},
  year      = {1994},
  pages     = {278-299},
  ee        = {http://dx.doi.org/10.1006/inco.1994.1073},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}