共 54 条
[1]
Bautin N. N.(1952)On the number of limit cycles which appear with the variation of coefficients from an equilibrium position of focus Mat. Sbornik 30 181-196
[2]
Bendixson I.(1900)Sur les courbes définies par des équations différentielles Acta Math. 24 1-88
[3]
Coppel W. A.(1989)Some quadratics systems with at most one limit cycle Dynam. report. Expositions Dynam. Systems (N.S.) 2 61-88
[4]
Cozma D.(1999)The solution of the problem of center for cubic differential systems with four invariant straight lines An. Stiint. Univ. Al. I. Cuza Iasi, Ser. Nuova, Mat. 44 517-530
[5]
Suba A.(2001)Solution of the problem of center for a cubic differential systems with three invariant straight lines Qual. Theory Dyn. Syst. 2 129-143
[6]
Cozma D.(2004)Coexistence of limit cycles and invariant algebraic curves on a Kukles systems Nonlinear Anal., Theory Methods Appl. 59 673-693
[7]
Suba A.(1979)Relative position and number of limit cycles of a quadratic differential system Acta Math. Sin. 22 751-758.
[8]
Chavarriga J.(1972)The limit cycles of some differential equations Differ. Uravn. 8 924-929
[9]
Sáez E.(1989)Quadratic systems having a parabola as an integral curve Proc. R. Soc. Edinb. Sect. A 112 113-134
[10]
Szántó I.(1989)Closed orbits and straight line invariants in Acta Mathematica Sci. 9 251-261