1. Optimal interstellar trajectories with acceleration-limited relativistic rockets;ANDERSON;Journal of the Astronautical Sciences,1968
2. Galactic matter and interstellar flight;BUSSARD;Astronautica Acta,1960
3. Interstellar flight;SHEPHERD;Journal of the British Interplanetary Society,1954
4. Relativity and space travel;PIERCE;Proceedings of the IRE,1959
5. On the mechanics of photon rockets;BURCEV;Astronomical Institute of Czechoslovakia Bulletin,1964