St\"ackel-type dynamic model of the Galaxy based on maser kinematic data
  A dynamic model of the Galaxy is constructed based on kinematic data for masers with trigonometric parallaxes. Maser data is used to compute the model potential in the Galactic plane. The potential is then generalized to three dimensions assuming the existence of a third quadratic integral of motion. The resulting Galactic model potential is of St\"ackel's type. The corresponding space density function is determined from Poisson's equation. 
A.O. Gromov, I.I. Nikiforov, L.P. Ossipkov
astro-ph.GA