Kramers-Kronig relations for the dielectric function and the static conductivity of Coulomb systemsV. B. Bobrov, S. A. Trigger, G. J. F. van Heijst and P. P. J. M. SchramEPL, 90 1 (2010) 10003DOI: https://doi.org/10.1209/0295-5075/90/10003