Yuan, Peng Fei et Zhang, Shi Qing, New periodic solutions for a class of singular Hamiltonian systems, Acta mathematica Sinica. English series (Print) , 29(6), 2013, pp. 1205-1218
In this paper, we apply a variant of the famous Mountain Pass Lemmas of Ambrosetti-Rabinowitz and Ambrosetti-Coti Zelati with (PSC)c type condition of Palais-Smale-Cerami to study the existence of new periodic solutions with a prescribed energy for symmetrical singular second order Hamiltonian conservative systems with weak force type potentials.