  It is analysed the triple-cut of one-loop amplitudes in dimensional
regularisation within spinor-helicity representation. The triple-cut is defined
as a difference of two double-cuts with the same particle content, and a same
propagator carrying, respectively, causal and anti-causal prescription in each
of the two cuts. That turns out into an effective tool for extracting the
coefficients of the three-point functions (and higher-point ones) from
one-loop-amplitudes. The phase-space integration is oversimplified by using
residues theorem to perform the integration over the spinor variables, via the
holomorphic anomaly, and a trivial integration on the Feynman parameter. The
results are valid for arbitrary values of dimensions.
