rétrograde
1984 / On the Retrograding of Planets / N. M. Swerdlow / Journal for the History of Astronomy 15 (1984) p. 30 [lien]
1998 / An Analysis of Ptolemy's Treatment of Retrograde Motion / D. MacMinn / Journal for the History of Astronomy 29 (1998) p. 257 [lien]
2005 / Using retrograde motion to understand and determine orbital parameters / Bruce G. Thompson / American Journal of Physics 73 (2005) p. 1023 [doi]