On Classification of Deformations of the Gardner Bracket Over Local   Infinitesimal Transformations
  The Lie algebra specified by space of local functionals with commutator determined by the Gardner bracket was under survey. Problem of classification of deformations of this bracket over local infinitesimal transformations of functionals was interpreted as a problem of computing the appropriate cohomology group of order 2. The most interesting class of deformations was investigated. 
V.L.Vereschagin