@incollection{Martin93-model,
  author	= {Martin, James R.},
  editor	= {Halliday, M. A. K. and Martin, J. R.},
  title		= {The model},
  booktitle	= {Writing Science: literacy as discursive power},
  address	= {London},
  publisher	= {Falmer},
  year		= {1993},
  pages		= {22--50}
}