  In this article we demonstrate a recently developed technique which addresses
the problem of obtaining non-universal prefactors of the correlation functions
of 1D systems at zero temperature. Our approach combines the effective field
theory description of generic 1D quantum liquids with the finite size scaling
of form factors (matrix elements) which are obtained using microscopic
techniques developed in the context of integrable models. We thus establish
exact analytic forms for the prefactors of the long-distance behavior of equal
time correlation functions as well as prefactors of singularities of dynamic
response functions. In this article our focus is on three specific integrable
models: the Calogero-Sutherland, Lieb-Liniger, and XXZ models.
