00310nam a2200121Ia 4500082001900000100001800019245005800037260003400095300002100129500002800150500000500178700000500183  a530.1bM397.TD  aMaslov, V. P.  aTheorie des perturbations et methodes asymptotiquesb  aParisbGauthier-Villarsc1972  axvi, 384p. Bibl.  a"Etudes Mathematiques".  a  a