Lagrange Anchor for Bargmann-Wigner equations
  A Poincare invariant Lagrange anchor is found for the non-Lagrangian relativistic wave equations of Bargmann and Wigner describing free massless fields of spin s > 1/2 in four-dimensional Minkowski space. By making use of this Lagrange anchor, we assign a symmetry to each conservation law. 
D. S. Kaparulin, S. L. Lyakhovich, A. A. Sharapov
math-ph hep-th math.MP