Relativistically covariant formulation of the canonical theory of   classical fields I
  An explicit Lorentz covariant formulation of the canonical theory for classical fields is established on a space-like hypersurface. Hamilton's equations and a Poisson bracket are defined on the space-like hypersurface. The Poisson bracket relations between total momentum and total angular momentum satisfies the Poincar{\'e} algebra. It is shown that our Poisson bracket has the same symplectic structure that was brought in the covariant symplectic approach. 
Hiroshi Ozaki