@incollection{Hornstein81,
  author	= {Hornstein, Norbert},
  editor	= {Hornstein, Norbert and Lightfoot, David},
  year		= {1981},
  title		= {The Study of Meaning in Natural Language: Three Approaches to Tense},
  booktitle	= {Explanation in Linguistics. The Logical Problem of Language Acquisition},
  publisher	= {Longman},
  address	= {London}
}