@Unpublished{K-theory/0856,
  author = 	 {{J. Wildeshaus}},
  title = 	 {{Pure motives, mixed motives and extensions of motives associated to singular surfaces}},
  note = 	 {{Preprint, June 30, 2007, K-theory Preprint Archives, http://www.math.uiuc.edu/K-theory/0856/}}}
}