@Unpublished{K-theory/0021,
  author = 	 {{M. S. Weiss and Bruce Williams}},
  title = 	 {{Products and Duality in Categories with Cofibration and Weak Equivalences}},
  note = 	 {{Preprint, August 16, 1994, K-theory Preprint Archives, http://www.math.uiuc.edu/K-theory/0021/}}}
}