@Unpublished{K-theory/0929,
  author = 	 {{Ivan Panin , Anastasia Stavrova , and Nikolai Vavilov }},
  title = 	 {{On Grothendieck-Serre's conjecture concerning principal G-bundles over reductive group schemes I }},
  note = 	 {{Preprint, May 10, 2009, K-theory Preprint Archives, http://www.math.uiuc.edu/K-theory/0929/}}}
}