[1] Coron J M. Periodic solutions of a nonlinear wave equation without monotonicity. Math Ann, 1983, 262: 273--285
[2] Del Pino M A, Man\'{a}sevich R F, Murua A. On the number of 2π periodic solutions for u''+g(u)=s(1+h(t)) using the Poincar\'e-Birkhoff theorem. J Differential Equations, 1992, 95(2): 240--258
[3] Ding T R. Nonlinear oscillations at a point of resonance. Sci Sinica Ser, 1982, 25A(9): 918--931
[4] Henderson J, Wang Haiyan. Positive solutions for nonlinear eigenvalue problems. J Math Anal Appl, 1997, 208: 252--259
[5] Ma R Y. Bifurcation from infinity and multiple solutions for periodic boundary value problems. Nonlinear Analysis, 2000, 42: 27--39
[6] Ma R Y, Thompson B. Nodal solutions for nonlinear eigenvalue problems. Nonlinear Analysis, 2004, 59: 707--718
[7] Marlin J A. Periodic motions of coupled simple pendulums with periodic disturbances. Int J Nonlinear Mech, 1968, 3: 439--447
[8] Mawhin J, Schmitt K. Landesman-Lazer type problems at an eigenvalue of odd multiplicity. Results in Mathematics, 1988, 14: 138--146
[9] Qian D B, Torres P J. Periodic motions of linear impact oscillators via the successor map. SIAM J Math Anal, 2005, 36(6): 1707--1725
[10] Rabinowitz P H. Some global results for nonlinear eigenvalue problems. J Funct Anal, 1971, 7: 487--513
[11] Wang H Y. Positive periodic solutions of functional differential equations. J Differential Equations, 2004, 202(2): 354--366
[12] Word Jr J R. Global bifurcation of periodic solutions to ordinary differential equations. J Differential Equations, 1998, 142: 1--16
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