共 11 条
[1]
Andreev A., 1958, Trans. Amer. Math. Soc, V8, P187
[3]
GAVRILOV L, 2005, ANN FAC SCI TOULOUSE, V14, P663
[4]
On second order bifurcations of limit cycles
[J].
JOURNAL OF THE LONDON MATHEMATICAL SOCIETY-SECOND SERIES,
1998, 58
:353-366
[5]
Ilyashenko Y., 1969, MAT SBORNIK, V78, P360
[6]
LI C, 2001, EXTRACTA MATH, V16, P441
[8]
Llibre J, 2001, DYNAM CONT DIS SER A, V8, P161
[9]
Perko L., 2001, Differential Equations and Dynamical Systems, Vthird, DOI DOI 10.1007/978-1-4613-0003-8
[10]
Spivak M.D., 1970, A comprehensive introduction to differential geometry