[1] Rabinowitz PH. Periodic solutions of Hamiltonian systems. Commun Pure Appl Math. 1978; 31: 157–184. [Crossref], [Web of Science ®], [Google Scholar]
[2] Ambrosetti A, Mancini G. Solutions of minimal period for a class of convex Hamiltonian systems. Math Ann. 1981; 255: 405–421. [Crossref], [Web of Science ®], [Google Scholar]
[3] Benci V, Capozzi A, Fortunato D. Periodic solutions of Hamiltonian systems of a prescribed period. Madison: University of Wisconsin; 1983. (MRC Tech. Sum. Report No. 2508). [Google Scholar]
[4] Brezis H, Coron JM. Periodic solutions of nonlinear wave equations and Hamiltonian systems. Amer J Math. 1981; 103: 559–570. [Crossref], [Web of Science ®], [Google Scholar]
[5] Clarke FH, Ekeland I. Hamiltonian trajectories having prescribed minimal period. Commun Pure Appl Math. 1980; 33: 103–116. [Crossref], [Web of Science ®], [Google Scholar]
[6] Ekeland I, Hofer H. Periodic solutions with prescribed period for convex autonomous Hamiltonian systems. Invent Math. 1985; 81: 155–188. [Crossref], [Web of Science ®], [Google Scholar]
[7] Fei G, Wang T. Some results on the minimal period problem of nonconvex second order Hamiltonian systems. Chin Ann Math. 1999; 20B: 83–92. [Crossref], [Web of Science ®], [Google Scholar]
[8] Girardi M, Matzeu M. Periodic solutions of convex autonomous Hamiltonian systems with a quadratic growth at the origin and superquadratic at infinity. Ann Mat Pura Appl. 1987; 147: 21–72. [Crossref], [Web of Science ®], [Google Scholar]
[9] Girardi M, Matzeu M. Existence of periodic solutions for some second order quasilinear Hamiltonian systems. Rend Lincei Mat Appl. 2007; 18: 1–9. [Google Scholar]
[10] Long Y. The minimal period problem for classical Hamiltonian systems with even potentials. Ann Inst H Poincaré Anal Non Linéaire. 1993; 10: 605–626. [Web of Science ®], [Google Scholar]
[11] Long Y. The minimal period problem of periodic solutions for autonomous superquadratic second order Hamiltonian systems. J Differential Equations. 1994; 111: 147–174. [Crossref], [Web of Science ®], [Google Scholar]
[12] Long Y. On the minimal period for periodic solutions of nonlinear Hamiltonian systems. Chin Ann Math. 1997; 18B: 481–484. [Google Scholar]
[13] Mawhin J, Willem M. Critical point theory and Hamiltonian systems. New York (NY): Springer; 1989. [Crossref], [Google Scholar]
[14] Rabinowitz PH. Critical point theory and applications to differential equations: a survey. In: Matzeu M, Vignoli A, editors. Topological nonlinear analysis. Boston (MA): Birkhauser; 1995. p. 464–513. [Crossref], [Google Scholar]
[15] D’Agui G, Livrea R. Periodic solutions for second order Hamiltonian systems. Le Matematiche. 2011; 66: 125–134. [Google Scholar]
[16] Xiao YM. Periodic solutions with prescribed minimal period for the second order Hamiltonian systems with even potentials. Acta Math Sinica English Ser. 2010; 26: 825–830. [Crossref], [Web of Science ®], [Google Scholar]
[17] Zhang X, Tang X. A note on the minimal periodic solutions of nonconvex superlinear Hamiltonian system. Appl Math Comput. 2013; 219: 7586–7590. [Crossref], [Web of Science ®], [Google Scholar]
[18] Precup R. A vector version of Krasnoselskii’s fixed point theorem in cones and positive periodic solutions of nonlinear systems. J Fixed Point Theory Appl. 2007; 2: 141–151. [Crossref], [Web of Science ®], [Google Scholar]
[19] Precup R. Two positive nontrivial solutions for a class of semilinear elliptic variational systems. J Math Anal Appl. 2011; 373: 138–146. [Crossref], [Web of Science ®], [Google Scholar]
[20] Precup R. On a bounded critical point theorem of Schechter. Studia Univ Babeş–Bolyai Math. 2013; 58: 87–95. [Google Scholar]
[21] Precup R. Critical point localization theorems via Ekeland’s variational principle. Dyn Syst Appl. 2013; 22: 355–370. [Web of Science ®], [Google Scholar]
[22] Struwe M. Variational methods. Berlin: Springer; 1990. [Crossref], [Google Scholar]