@article{Hudson67,
  author	= {Hudson, Richard A.},
  year		= {1967},
  title		= {Constituency in a systemic description of the English clause},
  journal	= {Lingua},
  volume	= {18},
  pages		= {225--250},
  note		= {Reprinted in Michael A.K. Halliday and James R. Martin (eds.)(1981) \em Readings in Systemic Linguistics, Batsford, London}
}