Quasiparticle transport equation with collision delay. I.   Phenomenological approach
  For a system of non-interacting electrons scattered by resonant levels of neutral impurities, we show that virial and quasiparticle corrections have nearly equal magnitudes. We propose a modification of the Boltzmann equation that includes quasiparticle and virial corrections and discuss their interplay on a dielectric function. 
V\'aclav \v{S}pi\v{c}ka, Pavel Lipavsk\'y, Klaus Morawetz