See "Meanest foundations and nobler superstructures: Hooke, Newton and the 'Compounding of the Celestial Motions of the Planets'", Ofer Gal, 2003 at page 9[collegamento interrotto].
See J. Bruce Brackenridge, "The key to Newton's dynamics: the Kepler problem and the Principia", (University of California Press, 1995), especially at pages 20-21[collegamento interrotto].