@Unpublished{K-theory/0716,
  author = 	 {{J. P. May and J. Sigurdsson}},
  title = 	 {{Parametrized homotopy theory}},
  note = 	 {{Preprint, November 30, 2004, K-theory Preprint Archives, http://www.math.uiuc.edu/K-theory/0716/}}}
}