  We report on (magneto)-transport experiments in chemically derived narrow
graphene nanoribbons under high magnetic fields (up to 60 Tesla). Evidences of
field-dependent electronic confinement features are given, and allow estimating
the possible ribbon edge symmetry. Besides, the measured large positive
magnetoconductance indicates a strong suppression of backscattering induced by
the magnetic field. Such scenario is supported by quantum simulations which
consider different types of underlying disorders (smooth edge disorder and long
range Coulomb scatters).
