by N. Kiriushcheva, P. G. Komorowski, and S. V. Kuzmin
We argue that the conclusion about the invalidity of the Dirac conjecture,
made in the paper by Wang, Li, and Wang (Int. J. Theor. Phys. 48 1894, 2009),
was based upon a flawed analysis of the proposed counterexamples. In the case
of the Maxwell theory, the well-known gauge symmetry is contradicted by the
results in the Hamiltonian and Lagrangian approaches presented by the authors.
We also consider the oldest counterexample to the Dirac conjecture due to
Allcock and present its natural parametrization.