  We provide a microscopic model setting that allows us to readily access to
the large-distance asymptotic behaviour of multi-point correlation functions in
massless, one-dimensional, quantum models. The method of analysis we propose is
based on the form factor expansion of the correlation functions and does not
build on any field theory reasonings. It constitutes an extension of the
restricted sum techniques leading to the large-distance asymptotic behaviour of
two-point correlation functions obtained previously.
