A Correction of the Paper 'Non-Characteristic Cauchy Problems and Genealized Goursat Problems in R^n ' Jan Persson Indiana University Mathematics Journal 1971 text pdf 10.1512/iumj.1971.20.20008 10.1512/iumj.1971.20.20008 en Indiana Univ. Math. J. 20 (1971) 95 - 95 state-of-the-art mathematics http://iumj.org/access/