Measures Orthogonal to Polydisc Algebras Frank Forelli Indiana University Mathematics Journal 1968 text pdf 10.1512/iumj.1968.17.17066 10.1512/iumj.1968.17.17066 en Indiana Univ. Math. J. 17 (1968) 1073 - 1086 state-of-the-art mathematics http://iumj.org/access/