A relativistic action-at-a-distance description of gravitational   interactions?
  It is shown that certain aspects of gravitation may be described using a relativistic action-at-a-distance formulation. The equations of motion of the model presented are invariant under Lorentz transformations and agree with the equations of Einstein's theory of General Relativity, at the first Post-Newtonian approximation, for any number of interacting point masses. 
Domingo J. Louis-Martinez
gr-qc hep-th math-ph math.MP