Representations of the Scattering Operator for Moving Obstacles J. CooperWalter Strauss Indiana University Mathematics Journal 1979 text pdf 10.1512/iumj.1979.28.28045 10.1512/iumj.1979.28.28045 en Indiana Univ. Math. J. 28 (1979) 643 - 671 state-of-the-art mathematics http://iumj.org/access/