Manifolds of Slow Solutions for Highly Oscillatory Problems Heinz-Otto KreissJens Lorenz Indiana University Mathematics Journal 1993 text pdf 10.1512/iumj.1993.42.42054 10.1512/iumj.1993.42.42054 en Indiana Univ. Math. J. 42 (1993) 1169 - 1191 state-of-the-art mathematics http://iumj.org/access/