  We explore gravitating relativistic spheres composed of an anisotropic,
barotropic uid. We assume a bi-polytropic equation of state which has a linear
and a power-law terms. The generalized Tolman-Oppenheimer-Volkoff (TOV)
equation which describes the hydrostatic equilibrium is obtained. The full
system of equations are solved for solutions which are regular at the origin
and asymptotically flat. Conditions for the appearance of horizon and a basic
treatment of stability are also discussed.
