\bibitem{Sapoval99}     B.Sapoval, M.Filoche, K.Karamanos, R.Brizzi \hskip 2mm
                        {\it Can one hear the shape of an electrode?
                        I. Numerical study of the active zone in Laplacian tranfer},
                        Eur. Phys. J. B {\bf 9}, 739-753, 1999.