Linearized perturbation on stationary inflow solutions in an inviscid   and thin accretion disc
  The influence of a linearized perturbation on stationary inflow solutions in an inviscid and thin accretion disc, has been studied here, and it has been argued, that a perturbative technique would indicate that all possible classes of inflow solutions would be stable. The choice of the driving potential, Newtonian or pseudo-Newtonian, would not particularly affect the arguments which establish the stability of solutions. It has then been surmised that in the matter of the selection of a particular solution, adoption of a non-perturbative technique, based on a more physical criterion, as in the case of the selection of the transonic solution in spherically symmetric accretion, would give a more conclusive indication about the choice of a particular branch of the flow. 
Arnab K. Ray