Real Analytic Maps on Manifolds P. ChurchW. Nathan Indiana University Mathematics Journal 1970 text pdf 10.1512/iumj.1970.19.19003 10.1512/iumj.1970.19.19003 en Indiana Univ. Math. J. 19 (1970) 19 - 36 state-of-the-art mathematics http://iumj.org/access/