Asymptotic Results for a Class of Integral Operators over Groups William Emerson Indiana University Mathematics Journal 1968 text pdf 10.1512/iumj.1968.17.17046 10.1512/iumj.1968.17.17046 en Indiana Univ. Math. J. 17 (1968) 737 - 758 state-of-the-art mathematics http://iumj.org/access/