Nonoscillation theorem for second-order linear equations

Let q:[0,infinity) → R, q not a.e. zero by a locally Lebesgue integrable function. We are interested in the existence of real constants c not equal to 0 such that the equation x'' + cq(t)x = 0 is nonoscillatory on [0,infinity). Applications to Bohr and Stepanoff almost-periodic functions q are included