  In this presentation we review recent results on the resummation of soft
gluon emission corrections for the associated production of a top-quark pair
with a heavy boson (Higgs/W/Z) at the Large Hadron Collider (LHC). We develop a
parton level Monte Carlo based on a soft-gluon resummation formula valid up to
next-to-next-to-leading logarithmic (NNLL) accuracy. With this tool we study
the impact of the newly computed corrections to the total cross sections and
some important differential distributions.
