@article{Seidl87Parameter,
  author = {Helmut Seidl},
  title = {Parameter {R}eduction of {H}igher {L}evel {G}rammars},
  journal = {Theor. Comput. Sci.},
  year = 1987,
  pages = {47-85},
  volume = {55},
  number = {1},
}