G. Rein, STATIC SOLUTIONS OF THE SPHERICALLY SYMMETRICAL VLASOV-EINSTEIN SYSTEM, Mathematical proceedings of the Cambridge Philosophical Society, 115, 1994, pp. 559-570
We consider the Vlasov Einstein system in a spherically symmetric sett
ing and prove the existence of static solutions which are asymptotical
ly flat and have finite total mass and finite extension of the matter.
Among these there are smooth. singularity-free solutions, which have
a regular centre and have isotropic or anisotropic pressure, and solut
ions which have a Schwarzschild-singularity at the centre.