Probing in-medium vector meson decays by double-differential di-electron spectra in heavy-ion collisions at SIS energiesGy. Wolf, B. Kämpfer and O. P. PavlenkoEur. Phys. J. Special Topics, 155 (2008) 223-230DOI: https://doi.org/10.1140/epjst/e2008-00604-4