  In this thesis the covariant Bethe-Salpeter equation formalism is used to
study some properties of ground-state baryons. This formalism relies on the
knowledge of the interaction kernel among quarks and of the full quark
propagator. For the interaction kernel, which is in principle a sum of
infinitely many diagrams, I use the Ladder truncation. It amounts to reduce the
interaction to a flavor-blind quark-mass independent vector-vector interaction
between two quarks, mediated by a dressed gluon. The irreducible three-body
interactions are neglected. The full quark propagator is obtained as a solution
of the quark Dyson-Schwinger equation which is truncated such that, together
with the truncation in the interaction kernel, chiral symmetry is correctly
implemented. It is called Rainbow truncation, and together with the truncated
kernel equation it constitutes the Rainbow-Ladder truncation of the
Bethe-Salpeter equation.
  Any truncation induces the introduction of a model to account for the
properties of the full system. The main goal of this thesis is to evaluate the
model dependence of corrsponding results and, as a consequence, to isolate the
features related to the truncation itself. To this end two non-related models
are used to calculate the baryon spectra, from light to heavy quarks, and the
electromagnetic properties of the Delta(1232). From these results one concludes
a qualitative model independence, and that a Rainbow-Ladder truncated
bound-state calculation reproduces the physical results with an accuracy of
~10%.
  Covariant bound-state equations are not limited to the study of hadronic
bound states. As an example, in a further chapter of this thesis a
Bethe-Salpeter equation for glueballs is proposed, and the main steps for a
consistent resolution of the equation are described. However, to obtain this
solution is beyond the scope of this work.
