@article{Had-Jol-Ngu-2005,
    author={Houssem Haddar and Patrick Joly and Hoai-Minh Nguyen },
    title={Generalized impedance boundary conditions for scattering by 
           strongly absorbing obstacles: the scalar case. },
    doi={10.1142/S021820250500073X },
    journal={Math. Models Methods Appl. Sci. },
    year={2005 },
    volume={15 (8) },
    pages={1273--1300},
}