共 50 条
- [33] PERIODIC-SOLUTIONS OF A 2ND-ORDER NONLINEAR DIFFERENTIAL-EQUATION SYSTEM WITH SIGN CHANGE ANNALI DI MATEMATICA PURA ED APPLICATA, 1990, 156 : 73 - 111
- [36] AN EXPANSION THEOREM FOR A 2ND-ORDER SINGULAR MATRIX DIFFERENTIAL-EQUATION INDIAN JOURNAL OF PURE & APPLIED MATHEMATICS, 1982, 13 (09): : 1049 - 1058
- [37] ON 2ND-ORDER DIFFERENTIAL-EQUATION OF LIMIT-CIRCLE TYPE KEXUE TONGBAO, 1983, 28 (12): : 1595 - 1599