More on Weak Estimates for Oscillating Kernels G. Sampson Indiana University Mathematics Journal 1979 text pdf 10.1512/iumj.1979.28.28035 10.1512/iumj.1979.28.28035 en Indiana Univ. Math. J. 28 (1979) 501 - 505 state-of-the-art mathematics http://iumj.org/access/