Mathisson Equations: Non-Oscillatory Solutions in a Schwarzschild Field
  The Mathisson equations under the Frenkel-Mathisson supplementary condition are studied in a Schwarzschild field. The choice of solutions, which describe the motions of the proper center of mass of a spinning test particle, is discussed, and the calculation procedure for highly relativistic motions is proposed. The very motions are important for astrophysics while investigating possible effects of the gravitational spin-orbit interaction on the particle's world line and trajectory. 
Roman Plyatsko, Oleksandr Stefanyshyn