Lipschitz Conditions and Quasiconformal Mappings Raimo NakkiBruce Palka Indiana University Mathematics Journal 1982 text pdf 10.1512/iumj.1982.31.31033 10.1512/iumj.1982.31.31033 en Indiana Univ. Math. J. 31 (1982) 377 - 401 state-of-the-art mathematics http://iumj.org/access/