TY - JOUR AU - Aberra, Dawit TI - On a generalized reflection law for functions satisfying the Helmholtz equation JO - Electronic Journal of Differential Equations PY - 1999 VL - 1999 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/EJDE_1999__1999__a123/ LA - en ID - EJDE_1999__1999__a123 ER -