Removable Sets for Quasiconformal Mappings Jussi Vaisala Indiana University Mathematics Journal 1970 text pdf 10.1512/iumj.1970.19.19006 10.1512/iumj.1970.19.19006 en Indiana Univ. Math. J. 19 (1970) 49 - 51 state-of-the-art mathematics http://iumj.org/access/