Products of Dilatations Dragomir Djokovic Indiana University Mathematics Journal 1977 text pdf 10.1512/iumj.1977.26.26040 10.1512/iumj.1977.26.26040 en Indiana Univ. Math. J. 26 (1977) 537 - 540 state-of-the-art mathematics http://iumj.org/access/