Abramowitz M., 1964, Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables, 55
Cairó L., Rend. Circ. Mat. Palermo, 52, 389, 10.1007/BF02872763
Christopher C., Electron. J. Differential Equations, 1999, 1
Christopher C., Ann. Differential Equations, 16, 5
Christopher C., Pacific J. Math., 229, 63, 10.2140/pjm.2007.229.63
Furta S. D., Z. Angew. Math. Phys., 47, 112, 10.1007/BF00917577
Kuznetsov Yu. A., 2000, Elements of Applied Bifurcation Theory, 112
Labrunie S., J. Math. Phys., 37, 5539, 10.1063/1.531721
Llibre J., J. Math. Phys., 48, 033507, 10.1063/1.2713076
Llibre J., J. Nonlinear Math. Phys., 16, 505, 10.1142/S1402925109000510
Llibre J., Proc. Amer. Math. Soc., 138, 3229, 10.1090/S0002-9939-10-10338-4
Llibre J., J. Geom. Phys., 60, 1974, 10.1016/j.geomphys.2010.08.005
Llibre J., Proc. Amer. Math. Soc., 138, 253, 10.1090/S0002-9939-09-10036-9
Llibre J., J. Math. Anal. Appl., 379, 188, 10.1016/j.jmaa.2010.12.033
Ollagnier J. Moulin, Bull. Sci. Math., 121, 463
Ollagnier J. Moulin, Bull. Sci. Math., 123, 437, 10.1016/S0007-4497(99)00111-6
Ollagnier J. Moulin, Qual. Theory Dyn. Syst., 2, 307, 10.1007/BF02969345
H. Poincaré, Mémoire sur les Courbes Définies par les Équations Différentielles (Oeuvreus de Henri Poincaré, I) (Gauthiers-Villars, Paris, 1951) pp. 95–114.
Singer M. F., Trans. Amer. Math. Soc., 333, 673, 10.1090/S0002-9947-1992-1062869-X
