Draessler, J.; Rachůnková, I.
(Нелінійні коливання, 2001)
We consider the periodic boundary-value problem x'' + a(t)x' + b(t)x = f(t, x, x'), x(') =x(2π), x'(0) = x' (2π), where a, b are Lebesgue integrable functions and f fulfils the
Caratheodory conditions. We extend results ...