@Unpublished{K-theory/0871,
  author = 	 {{Bruno Kahn  and Georges Maltsiniotis }},
  title = 	 {{Structures de dérivabilité }},
  note = 	 {{Preprint, October 1, 2007, K-theory Preprint Archives, http://www.math.uiuc.edu/K-theory/0871/}}}
}