Sur L'Integration des Equations de la Relativite Generale Madame Yvonne Foura¨s-Bruhat Indiana University Mathematics Journal 1956 text pdf 10.1512/iumj.1956.5.55036 10.1512/iumj.1956.5.55036 en Indiana Univ. Math. J. 5 (1956) 951 - 966 state-of-the-art mathematics http://iumj.org/access/