共 27 条
[1]
Bautin N. N., 1952, MAT SBORNIK, V30, P181
[3]
Chen L.S., 1979, ACTA MATH SINICA, V22, P751
[7]
Dulac H., 1923, B SOC MATH FR, V51, P45, DOI [10.24033/bsmf.1031, DOI 10.24033/BSMF.1031]
[9]
Hilbert D, 1902, B AM MATH SOC, V8, P437, DOI [10.1090/S0002-9904-1902-00923-3, DOI 10.1090/S0002-9904-1902-00923-3]
[10]
LEFCHETZ S, 1957, DIFFERENTIAL EQUATIO