$L^p$ bounds for singular integrals and maximal singular integrals with rough kernels Loukas GrafakosAtanas Stefanov 42B20singular integralsrough kernelsCalderon-Zygmund operator Indiana University Mathematics Journal 1998 text pdf 10.1512/iumj.1998.47.1521 10.1512/iumj.1998.47.1521 en Indiana Univ. Math. J. 47 (1998) 455 - 470 state-of-the-art mathematics http://iumj.org/access/