Abstract :
An oscillation criterion is given for the differential equation ddt1an−1(t)ddt•••ddt1a1(t)ddtx(t) + f(t, x[g1(t)], ..., x[gm(t)]) = 0,n even. The obtained result is new, even for the linear differential equation x(n)(t) + q(t)x(t) = 0, n even.