  We discuss an application of the method of the angular quantization to
reconstruction of form-factors of local fields in massive integrable models.
The general formalism is illustrated with examples of the Klein-Gordon,
sinh-Gordon and Bullough-Dodd models. For the latter two models the angular
quantization approach makes it possible to obtain free field representations
for form-factors of exponential operators. We discuss an intriguing relation
between the free field representations and deformations of the Virasoro
algebra. The deformation associated with the Bullough-Dodd models appears to be
different from the known deformed Virasoro algebra.
