00447nam a2200121Ia 4500082001900000100003600019245009700055260004300152300001000195490008400205500000500289700003100294  a515.35bK96.SL  aKaumpera, A. and Spencer, D. C.  aSystems of linear partial differential equations and deformation of pseudogroup structuresb  aMontrealbUniversite de Montrealc1974  a104p.  aUniversity of Montreal, seminaire de Mathematiques superieures-ETE 1969v v. 41  a  aSpencer, D. C. ; jt. auth.