1854, Dionysius Lardner, Hand-books of Natural Philosophy and Astronomy, It results, however, from what has been proved, that if the perijove be in conjunction, the disturbing force of s" will render the apsides of s' regressive, and if the apojove be in conjunction, it will render that motion progressive. But since the motion of the apsides of s' is regressive, the perijove must be in conjunction.
2006, Keith S. Noll, ‎Harold A. Weaver, ‎& Paul D. Feldman, The Collision of Comet Shoemaker-Levy 9 and Jupiter: IAU Colloquium 156, It is interesting to integrate the orbit solutions backward to the 1992 perijove to see how closely the fragments come together.
2012, Christopher Russell, The Galileo Mission, Flybys that change the orbital period also rotate the line of apsides and change the perijove distance.
