@article{1183511677,
author = {Synge, J. L.},
title = {Apsidal angles for symmetrical dynamical systems with two degrees of freedom},
journal = {Bull. Amer. Math. Soc.},
volume = {54},
number = {12},
year = {1948},
pages = { 111-118},
language = {en},
url = {http://dml.mathdoc.fr/item/1183511677}
}
Synge, J. L. Apsidal angles for symmetrical dynamical systems with two degrees of freedom. Bull. Amer. Math. Soc., Tome 54 (1948) no. 12, pp. 111-118. http://gdmltest.u-ga.fr/item/1183511677/