  In the Catani-Ciafaloni-Hautmann high-energy factorization approach a cross
section is expressed as a convolution of unintegrated gluon densities and a
gauge-invariant hard process, in which two incoming gluons are off-shell with
momenta satisfying certain high-energy kinematics. We present two methods of
evaluating the tree-level hard process with multiple final states. The first
one assumes that only one of the gluons is off-shell and relies on the
Slavnov-Taylor identities. Such asymmetric configuration of incoming gluons is
phenomenologically important in small x probing by forward processes. The
second method deals also with two off-shell gluons and is based on the analytic
continuation of the off-shell gluons momenta to the complex space. The methods
were implemented into Monte Carlo computer programs and used in
phenomenological applications. The results of both methods are
straightforwardly related to Lipatov's effective vertices in quasi-multi-regge
kinematics.
