@incollection{Kress85-socio,
  author	= {Kress, Gunther},
  editor	= {Wells, G. and Nicholls, J.},
  year		= {1985},
  title		= {Sociolinguistic development and the mature language user},
  booktitle	= {Language and Learning: an international perspective},
  publisher	= {Falmer},
  address	= {London}
}