Comment on `Hamiltonian formulation for the theory of gravity and   canonical transformations in extended phase space' by T P Shestakova
  We argue that the conclusion, `we cannot consider the Dirac approach as fundamental and undoubted', made in the paper by Shestakova (Class. Quantum Grav. 28 055009, 2011), is based upon an incomplete and flawed analysis of the simple model presented in section 3 of the article. We re-examine the analysis of this model and find that it does not support the author's conclusion. For the theory of gravity neither the equivalence of the effective action nor its Hamiltonian formulation is given by the author, therefore, we only provide a brief commentary. 
N. Kiriushcheva, P.G. Komorowski and S.V. Kuzmin
gr-qc