1. Andreu, M.A. (in preparation) The Quasibicircular Problem, Thesis, Dept. Matemàtica Aplicada i Anàlisi, Universitat de Barcelona.
2. Farquhar, R.W. (1971) The Utilization of Halo Orbits in Advanced Lunar Operations, NASA TN D-6365.
3. Gómez G., Jorba A., Masdemont J. and Simó C. (1991) Study refinement of semianalytical halo orbit theory, ESOC contract 8625/89/D/MD(SC), Final Report.
4. Marchal, C. (1990) The Three-Body Problem, Elsevier.
5. Richardson, D.L. (1980) A note on a Lagragian formulation for motion about the collinear points, Celestial Mechanics 22, 231–236.