  High energy strong interaction physics is successfully described by the local
renormalizable gauge theory called Quantum-Chromo-Dynamics (QCD) with quarks
and gluons as ``elementary'' degrees of freedom, while intermediate energy
strong interaction physics shows up to be determined by a non-local,
non--renormalizable effective field theory (EFT) of ``effective'' degrees of
freedom like mesons, ground state baryons and resonances. Within the picture of
an effective field theory of strong interaction at intermediate energies I
present a ``toy-model'' in which fermionic and bosonic resonances are
considered to be ``particles'', i.e. they consistently are described by
(anti-)commuting effective field-operators (containing dynamics of infinitely
many quark-gluon or meson-nucleon diagrams) which are comfortably treated by
Wick's Theorem in a covariant framework and obey unitarity. Non-trivial
implications to couplings of non-local interactions are shown.
