1. Bradley, W. A., Astron. Aeronaut., 6, No. 4 (1968).
2. Hult, J. L., The Technology Potentials for Satellite Spacing and Frequency Sharing, Rand Corporation, Memorandum RM-5785-NASA (1968).
3. Arnaud, J. F., Frequency Assignment Plans for Synchronous Communications Satellites, J. Spacecraft Rockets, 6, No. 4 (1969).
4. Frick, R. H., and Gerber, T. B., Perturbations of a Synchronous Satellite, Rand Corporation, Report R-399 (1962).
5. Balsam, R. E., and Dunin, S. E., Orbit Determination for Stationary Satellites, 11, 123, Science and Technology Series (American Astronautical Society, 1967).