@Unpublished{K-theory/0935,
  author = 	 {{Nikita A. Karpenko}},
  title = 	 {{Hyperbolicity of orthogonal involutions}},
  note = 	 {{Preprint, June 17, 2009, K-theory Preprint Archives, http://www.math.uiuc.edu/K-theory/0935/}}}
}