A functional differential equation of the type x '' = (Fx) (t), where
F : C-1(J) --> L-1(J) is a unbounded operator, is considered. Sufficie
nt conditions for the existence of at least two different solutions sa
tisfying boundary conditions min{x(t) : t is an element of J} = alpha,
max{x(t) : t is an element of J} = beta are given.