  In a recent paper [T. C. Ralph, W. J. Munro, R. E. S. Polkinghorne, Phys.
Rev. Lett. 85, 2035 (2000)], the authors propose a test for Bell's inequalities
based on quadrature measurements for a correlated parametric source. We present
here a local hidden variable model which reproduces all the expectation values
predicted in the described experimental scheme, and point out that the proposal
is based on an inconsistent use of Bell's inequalities.
