  The existence of non-local charges, generating a Yangian symmetry is
discussed in generalized chiral Gross-Neveu models. Their conservation can be
proven by a finite-loop perturbative computation, the order of which is
determined from group theoretic constants and is independent of the number of
flavors. Examples, where the 1-loop calculation is sufficient, include the
SO(n)-models and other more exotic groups and representations.
