On the comparison of results regarding the post-Newtonian approximate   treatment of the dynamics of extended spinning compact binaries
  A brief review is given of all the Hamiltonians and effective potentials calculated hitherto covering the post-Newtonian (pN) dynamics of a two body system. A method is presented to compare (conservative) reduced Hamiltonians with nonreduced potentials directly at least up to the next-to-leading-pN order. 
Steven Hergt, Jan Steinhoff and Gerhard Schaefer
gr-qc