A New Formula for the Mass of a Stationary Axisymmetric Configuration
  It has been shown by one of the authors$^1$ that in isotropic spherical coordinates there is a relation between the mass of a static spherical gravitating body and the pressure distribution inside it. In this paper the result is generalized for the case of stationary axisymmetric configurations. 
R. M. Avakian and G. Oganessyan