ハロー軌道
↑ Farquhar, R. W.: "The Control and Use of Libration-Point Satellites", Ph.D. Dissertation, Dept. of Aeronautics and Astronautics, Stanford University, Stanford, CA, 1968
↑ Dunham, D.W. and Farquhar, R. W.:"Libration-Point Missions 1978-2000," Libration Point Orbits and Applications, Parador d'Aiguablava, Girona, Spain, June 2002
↑ Howell, K. C.: "Three-Dimensional, Periodic, 'Halo' Orbits", Celestial Mechanics, Volume 32, Number 53, 1984