A Class of Quasi-Pseudo-Conformal Transformations in the Theory of Functions of Two Complex Variables Stefan Bergman Indiana University Mathematics Journal 1958 text pdf 10.1512/iumj.1958.7.57054 10.1512/iumj.1958.7.57054 en Indiana Univ. Math. J. 7 (1958) 937 - 956 state-of-the-art mathematics http://iumj.org/access/