@article{DBLP:journals/tcs/Bordihn04,
  author    = {Henning Bordihn},
  title     = {Context-freeness of the power of context-free languages
               is undecidable},
  journal   = {Theor. Comput. Sci.},
  volume    = {314},
  number    = {3},
  year      = {2004},
  pages     = {445-449},
  ee        = {http://dx.doi.org/10.1016/j.tcs.2003.08.005},
  bibsource = {DBLP, http://dblp.uni-trier.de}
}