ENFOQUE

• The meaning of fossils : episodes in the history of paleontology
  RUDWICK M.J
  The University of Chicago Press ed.
  1985
• Le vivant créateur de son évolution
  WINTREBERT P.
  Masson, Paris
  1978
• An Introduction to Abstract Algebra, Vol. 1, 2nd edition
  HALL F.M.
  1972.
• Earth : the making, shaping and working of a planet
  ELSOM D.
  1992