Beeri75'

@article{DBLP:journals/jcss/Beeri75,
  author    = {Catriel Beeri},
  title     = {Two-Way Nested Stack Automata Are Equivalent to Two-Way
               Stack Automata},
  journal   = {J. Comput. Syst. Sci.},
  volume    = {10},
  number    = {3},
  year      = {1975},
  pages     = {317-339},
  ee        = {http://dx.doi.org/10.1016/S0022-0000(75)80004-3},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}