@Unpublished{K-theory/0854,
  author = 	 {{Nikita A. Karpenko and Alexander S. Merkurjev}},
  title = 	 {{Essential dimension of finite groups}},
  note = 	 {{Preprint, June 25, 2007, K-theory Preprint Archives, http://www.math.uiuc.edu/K-theory/0854/}}}
}