Some remarks on nonlinear second-order differential equations with periodic boundary conditions
1989 ◽
Vol 139
(2)
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pp. 465-476
1978 ◽
Vol 80
(3-4)
◽
pp. 357-362
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1979 ◽
Vol 84
(3-4)
◽
pp. 249-257
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2021 ◽
Vol 67
(6)
◽
pp. 119-124
2019 ◽
Vol 43
(9)
◽
pp. 1311-1330
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