@incollection{Huddleston81-features,
  author	= {Huddleston, Rodney D.},
  editor	= {Halliday and Martin},
  year		= {1981},
  title		= {Systemic features and their realization},
  booktitle	= {Readings in Systemic Linguistics},
  publisher	= {Batsford},
  address	= {London}
}