1. A linear theory of optimum low-thrust rendezvous trajectories;Gobetz;JAS,1965
2. Optimum low-thrust rendezvous and station keeping;Edelbaum;AIAA J.,1964
3. Optimum low-thrust limited-power transfers between arbitrary elliptical orbits;Marec;Acta Astronautica,1977
4. On the equinoctial orbit elements;Broucke;Celestial Mech.,1972
5. Equinoctial orbit elements: application to artificial satelite orbits;Cefola,1972