@Article{Se03b,
  author = 	 {Jos\'e M. Sempere},
  title = 	 {A note on the equivalence and complexity of linear grammars},
  journal = 	 {Grammars},
  year = 	 {2003},
  volume =       {6},
  number = 	 {2},
  pages = 	 {115--226}
}