On the Theory of Lipschitz Spaces of Distributions on Euclidean n-Space. III. Smoothness and Integrability of Fourier Tansforms, Smoothness of Convolution Kernels Mitchell Taibleson Indiana University Mathematics Journal 1966 text pdf 10.1512/iumj.1966.15.15065 10.1512/iumj.1966.15.15065 en Indiana Univ. Math. J. 15 (1966) 973 - 981 state-of-the-art mathematics http://iumj.org/access/