Robert Farquhar (1966). Station-Keeping in the Vicinity of Collinear Libration Points with an Application to a Lunar Communications Problem. AAS Science and Technology Series: Space Flight Mechanics Specialist Symposium. 11: 519—535., see Farquhar, R. W.: «The Control and Use of Libration-Point Satellites», Ph.D. Dissertation, Dept. of Aeronautics and Astronautics, Stanford University, Stanford, California, 1968, pp. 103, 107—108.