The rotation curve and mass-distribution in highly flattened galaxies
  A new method is developed which permits the reconstruction of the surface-density distribution in the galactic disk of finite radius from an arbitrary smooth distribution of the angular velocity via two simple quadratures. The existence of upper limits for disk's mass and radius during the analytic continuation of rotation curves into the hidden (non-radiating) part of the disk is demonstrated. 
N.R. Sibgatullin, A.A. Garcia, V.S. Manko