@article{Buf-Cia-2001,
    author={Annalisa Buffa and Patrick Ciarlet },
    title={On traces for functional spaces related to Maxwell's 
           equations. Part I: an integration by parts formula in 
           Lipschitz polyhedra },
    journal={Mathematical Methods in the Applied Sciences },
    year={2001 },
    volume={24 (1) },
    pages={9--30},
}