  We present a systematic method for reducing an arbitrary one-loop N-point
massless Feynman integral with generic 4-dimensional momenta to a set comprised
of eight fundamental scalar integrals: six box integrals in D=6, a triangle
integral in D=4, and a general two-point integral in D space time dimensions.
All the divergences present in the original integral are contained in the
general two-point integral and associated coefficients. The problem of
vanishing of the kinematic determinants has been solved in an elegant and
transparent manner. Being derived with no restrictions regarding the external
momenta, the method is completely general and applicable for arbitrary
kinematics. In particular, it applies to the integrals in which the set of
external momenta contains subsets comprised of two or more collinear momenta,
which are unavoidable when calculating one-loop contributions to the
hard-scattering amplitude for exclusive hadronic processes at large momentum
transfer in PQCD. The iterative structure makes it easy to implement the
formalism in an algebraic computer program.
