A source of a quasi--spherical space--time: The case for the M--Q   solution
  We present a physically reasonable source for an static, axially--symmetric solution to the Einstein equations. Arguments are provided, supporting our belief that the exterior space--time produced by such source, describing a quadrupole correction to the Schwarzschild metric, is particularly suitable (among known solutions of the Weyl family) for discussing the properties of quasi--spherical gravitational fields. 
L. Herrera, W. Barreto and J.L. Heren\'andez Pastora