  A compact method for amplitude calculations in theories with Dirac and
Majorana effective operators is discussed. Using the renormalizable formalism
of Denner et al., [1,2] for propagators, vertices and fermion (number) flow and
introducing new "reading-rules", it is shown that fermions can be treated as
scalars in the diagrams. The effect of Fermi-statistics appears only in overall
signs and is determined once for whole classes of diagrams. Each vertex in this
method corresponds to two or more vertices in the standard treatment of
effective theories. As such, the advantages of this approach grow together with
the number of four-fermion vertices in a given diagram. The discussion develops
around effective field theories based on the Standard Model, up to
four-fermions and to any order in perturbation theory. Even so, the framework
is more general and can be applied elsewhere.
