@Unpublished{K-theory/0090,
  author = 	 {{Nikita A. Karpenko}},
  title = 	 {{Codimension 2 cycles on Severi-Brauer varieties}},
  note = 	 {{Preprint, November 18, 1995, K-theory Preprint Archives, http://www.math.uiuc.edu/K-theory/0090/}}}
}