  We briefly sketch the methods for a numerically stable evaluation of tensor
one-loop integrals that have been used in the calculation of the complete
electroweak one-loop corrections to $\Pep\Pem\to4 $fermions. In particular, the
improvement of the new methods over the conventional Passarino--Veltman
reduction is illustrated for some 4-point integrals in the delicate limits of
small Gram (and other kinematical) determinants.
