Existence of periodic solutions of Hamiltonian systems with potential indefinite in sign

[1] ON SEMILINEAR ELLIPTIC-EQUATIONS WITH INDEFINITE NONLINEARITIES [J]. CALCULUS OF VARIATIONS AND PARTIAL DIFFERENTIAL EQUATIONS, 1993, 1 (04) : 439 - 475

[2] SOLUTIONS OF MINIMAL PERIOD FOR A CLASS OF CONVEX HAMILTONIAN-SYSTEMS [J]. MATHEMATISCHE ANNALEN, 1981, 255 (03) : 405 - 421

[3] Ambrosetti A., 1993, Rend. Sem. Mat. Univ. Padova, V89, P177

[4] [Anonymous], 1994, COMM APPL NONLINEAR

[5] EXISTENCE AND MULTIPLICITY RESULTS FOR HOMOGENEOUS 2ND-ORDER DIFFERENTIAL-EQUATIONS [J]. JOURNAL OF DIFFERENTIAL EQUATIONS, 1994, 112 (01) : 239 - 249

[6] Ding Y., 1993, Dyn. Syst. Appl, V2, P131

[7] Girardi M, 1995, NODEA-NONLINEAR DIFF, V2, P35, DOI 10. 1007/BF01194013

[8] PERIODIC-SOLUTIONS OF A 2ND-ORDER SUPERQUADRATIC SYSTEM WITH A CHANGE OF SIGN IN THE POTENTIAL [J]. JOURNAL OF DIFFERENTIAL EQUATIONS, 1991, 93 (01) : 1 - 18

[9] Lassoued L., 1990, ANN MAT PUR APPL, V156, P76, DOI 10. 1007/BF01766974

[10] Zelati VC., 1991, J AM MATH SOC, V4, P693

[1] ON SEMILINEAR ELLIPTIC-EQUATIONS WITH INDEFINITE NONLINEARITIES [J]. CALCULUS OF VARIATIONS AND PARTIAL DIFFERENTIAL EQUATIONS, 1993, 1 (04) : 439 - 475

[2] SOLUTIONS OF MINIMAL PERIOD FOR A CLASS OF CONVEX HAMILTONIAN-SYSTEMS [J]. MATHEMATISCHE ANNALEN, 1981, 255 (03) : 405 - 421

[3] Ambrosetti A., 1993, Rend. Sem. Mat. Univ. Padova, V89, P177

[4] [Anonymous], 1994, COMM APPL NONLINEAR

[5] EXISTENCE AND MULTIPLICITY RESULTS FOR HOMOGENEOUS 2ND-ORDER DIFFERENTIAL-EQUATIONS [J]. JOURNAL OF DIFFERENTIAL EQUATIONS, 1994, 112 (01) : 239 - 249

[6] Ding Y., 1993, Dyn. Syst. Appl, V2, P131

[7] Girardi M, 1995, NODEA-NONLINEAR DIFF, V2, P35, DOI 10. 1007/BF01194013

[8] PERIODIC-SOLUTIONS OF A 2ND-ORDER SUPERQUADRATIC SYSTEM WITH A CHANGE OF SIGN IN THE POTENTIAL [J]. JOURNAL OF DIFFERENTIAL EQUATIONS, 1991, 93 (01) : 1 - 18

[9] Lassoued L., 1990, ANN MAT PUR APPL, V156, P76, DOI 10. 1007/BF01766974

[10] Zelati VC., 1991, J AM MATH SOC, V4, P693