  We evaluate differential cross sections for production of four jets in
multi-Regge kinematics at a hadron collider. The main focus lies on azimuthal
angle dependences. As in previous studies, the ratios of correlation functions
of products of cosines of azimuthal angle differences among the tagged jets
offer us the cleanest quantities to compare with experimental data. The
calculations are based on the jet production from a single BFKL ladder with a
convolution of three BFKL Green functions where we always have two
forward/backward jets tagged in the final state. We also demand the tagging of
two further jets in more central regions of the detectors with a relative
separation in rapidity from each other, plus the inclusive production of an
arbitrary number of mini-jets. We show that dependences on the transverse
momenta and rapidity of the two central jets can be a distinct signal of the
onset of BFKL dynamics.
