  In this paper one examine analytical solutions for flat and non-flat
universes composed by four components namely hot matter (ultra-relativistic),
warm matter (relativistic), cold matter (non-relativistic) and cosmological
constant. The warm matter is treated as a reduced relativistic gas and the
other three components are treated in the usual way. The solutions achieved
contains one, two or three components of which one component is of warm matter
type. A solution involving all the four components was not found.
