  We present a theory presenting new quantum oscillations in the
magnetoresistance that are revealed as fine structures superimposed to the
Schubnikov-de-Haas oscillations. They may be observed in experiments on
graphene layers as fine structures that until now seem to have been overseen or
considered to be noise. These oscillations appear also in the behaviour of the
resistance as a function of the gate voltage that changes the number of
carriers or Fermi level. Experimental studies of these resonances should give
information of the uniformity and defects of the samples and represent a new
fine structure spectroscopy. Also the lateral sample size and quantum effects
may explain the absence of magnetoresistance in a few grapheme layers.
Experiments are proposed.
