Revisiting the Eichten - Feinberg - Gromes Q \bar{Q} Spin-Orbit   Interaction
  Invariant and covariant forms of the quark-antiquark interaction derived by the method of Eichten and Feinberg are considered. Relations between the various terms imposed by Lorentz transformation constraints, here called Gromes relations, are found to exist in neither case. Details of the Gromes relation proper are reconsidered and inconsistencies found that lead to a violation of covariance. 
K.Williams