Partial Differential Equations with More than Two Independent Variables in the Complex Domain P. Garabedian Indiana University Mathematics Journal 1960 text pdf 10.1512/iumj.1960.9.59015 10.1512/iumj.1960.9.59015 en Indiana Univ. Math. J. 9 (1960) 241 - 271 state-of-the-art mathematics http://iumj.org/access/