1. Bien, R., Schubart, J.: 1987, ?Three characteristic orbital parameters for the Trojan group of asteroids?,Astron. Astrophys. 175, pp. 292?298
2. Brouwer, D., Van Woerkom, A.J.J.: 1950, ?The secular variations of the orbital elements of the principal planets?,Astronomical Papers Washington 13, Part 2, pp. 81?107
3. Carpino, M., Milani, A., Nobili, A.M.: 1987, ?Long-term numerical integrations and synthetic theories for the motion of the outer planets?,Astron. Astrophys. 181, pp. 182?194
4. Colombo, G., Franklin, F.A., Munford, C.M.: 1968, ?On a family of periodic orbits of the restricted three-body problem and the question of the gaps in the asteroid belt and in Saturn's rings?,Astron. J. 73, pp. 111?123
5. Ferraz-Mello, S.: 1987, ?Averaging the elliptic asteroidal problem near a first-order resonance?,Astron. J. 94, pp. 208?212