  We perform a NLO analysis of polarized deep inelastic scattering data to test
two different solutions to the so called spin crisis: one of them based on the
axial gluon anomaly and consistent with the Bjorken sum rule and another one,
where the defects in the spin sum rules and in the Gottfried sum rule are
related. In this case a defect is also expected for the Bjorken sum rule. The
first solution is slightly favoured by the SLAC E154 results, but both options
seem to be consistent with the CERN SMC data.
