Re iλSpx,yq Kpx, yqψpx, yqf pyqdy, (0.1)where the phase functions are homogeneous polynomials of degree n and the singular kernel Kpx, yq satisfies suitable conditions related to a real parameter µ. We show that the sharp decay estimates on L 2 spaces, obtained in [4], can be preserved on more general L p spaces with an additional condition imposed on the singular kernel. In fact, we obtain that´µ . The case without the additional condition is also discussed.