Minimal Gravitomagnetism
  We show that Feynman's proof applies to Newtonian gravitation, implying thus the existence of gravitational analogous of the electric and magnetic fields and the corresponding Lorentz-like force. Consistency of the formalism require particular properties of the electric and magnetic-like fields under Galilei transformations, which coincide with those obtained in previous analysis of Galilean electromagnetism. 
C. A. Vaquera-Araujo and J. L. Lucio M