Spatially open Friedmann--Robertson--Walker Universe fueled with   interacting sources
  In the present paper, we are analyzing the $k=-1-$FRW Universe with two interacting ideal fluids. The energy densities and the pressures are used to derive the corresponding Equations of State. For a particular form of the interaction term between the two fluids, it turns out that the Universe is filled with a mixture of dust and radiation. 
Marina-Aura Dariescu and Ciprian Dariescu
physics.gen-ph