Formation and migration of trans-Neptunian objects and asteroids
  The evolution of thousands of orbits of Jupiter-family comets and asteroids under the gravitational influence of planets was calculated. Comparison of the results obtained by a symplectic method with those obtained by direct integration showed that a symplectic method is not always good for investigations of the orbital evolution of such bodies. Basing on the results of orbital evolution of bodies, we concluded that a considerable portion of near-Earth objects could have come from the trans-Neptunian region. Some large trans-Neptunian objects could be formed by the compression of rarefied dust condensations, but not by the accumulation of smaller planetesimals. 
S.I. Ipatov