  We present a self-consistent theory for the description of the spectroscopic
properties of odd nuclei which includes exact blocking, particle-number and
angular-momentum projection and configuration mixing. In our theory the pairing
correlations are treated in a variation-after-projection approach and the
triaxial deformation parameters are explicitly considered as generator
coordinates. The angular-momentum and particle-number symmetries are exactly
recovered. The use of the effective finite-range density-dependent Gogny force
in the calculations provides an added value to the theoretical results.
  We apply the theory to the textbook example of 25Mg and, although this
nucleus has been thoroughly studied in the past, we still provide a novel view
of nuclear phenomena taking place in this nucleus. We obtain an overall good
agreement with the known experimental energies and transition probabilities
without any additional parameter such as effective charges. In particular, we
clearly identify six bands, two of which we interpret as collective gamma
bands.
