Erratum to “Time harmonic wave diffraction problems in materials with sign-shifting coefficients” [J. Comput. Appl. Math. doi:10.1016/j.cam.2009.08.041]

We mention here an error in the statement of the configurations that are covered by the theory of T -coercivity presented in the paper “Time harmonic wave diffraction problems in materials with sign-shifting coefficients” [J. Comput. Appl. Math. doi:10.1016/j.cam.2009.08.041].