Translation-Dilation Invariant Estimates for Riesz Potentials David AdamsRichard Bagby Indiana University Mathematics Journal 1974 text pdf 10.1512/iumj.1974.23.23086 10.1512/iumj.1974.23.23086 en Indiana Univ. Math. J. 23 (1974) 1051 - 1067 state-of-the-art mathematics http://iumj.org/access/