In this paper some oscillation criteria are established for equation [q(t)y’] +a(t)f(y) = 0, where a(t) is not assumed to be non-negative and f(y) is nodecreasing in y, and yf(y) > 0 for y≠0, f(y) also satisfics a sublinear condition, q(t) is a positive function on [0, ). These results extend earlier oscillation theorems of Philos and Wong.
