  A method to find relations between the operators in the mesonic Lagrangian of
Chiral Perturbation Theory at order p^6 is presented. The procedure can be used
to establish if the basis of operators in the Lagrangian is minimal. As an
example, we apply the method to the two-flavour case in the absence of scalar
and pseudo-scalar sources (s=p=0), and conclude that the minimal Lagrangian
contains 27 independent operators.
