@incollection{Berry81,
  author	= {Berry, Margaret},
  editor	= {Coulthard, Malcolm and Montgomery, Michael},
  year		= {1981},
  title		= {Systemic linguistics and discourse analysis: a multi-layered approach to exchange structure},
  booktitle	= {Studies in Discourse Analysis},
  publisher	= {Routledge and Kegan Paul},
  pages		= {120--145},
  address	= {London}
}