Existence of periodic solutions to second-order Hamiltonian systems with potential indefinite in sign
2002 ◽
Vol 51
(7)
◽
pp. 1273-1283
◽
2018 ◽
Vol 13
(6)
◽
pp. 1313-1323
◽
Keyword(s):
2021 ◽
Vol 58
◽
pp. 103218
2014 ◽
Vol 13
(1)
◽
pp. 75-95
◽