%0 Journal Article %A I. A. Kolesnikova %T Necessary and sufficient conditions for the existence of symmetry groups for systems of differential-difference equations with partial derivatives %J Contemporary Mathematics. Fundamental Directions %D 2010 %P 5-15 %V 37 %I mathdoc %U http://geodesic.mathdoc.fr/item/CMFD_2010_37_a0/ %G ru %F CMFD_2010_37_a0