Different representations of an effective, covariant theory of the hadronic interaction are examined. For this purpose we have introduced nucleon-meson vertices parametrized in terms of scalar combinations of hadronic fields, extending the conceptual frame of the density-dependent hadronic field theory. Nuclear matter properties at zero temperature are examined in the mean-field approximation, including the equation of state, the Landau parameters, and collective modes. The treatment of isospin channels, which includes quantum chromodynamics sum-rules inputs, is outlined.Facultad de Ciencias Exactas