00421nam a2200157Ia 4500008004100000082001600041100001700057245005800074260003400132300000800166650001600174650001800190653001300208653002700221653001500248170901s1970    xx            000 0 und d  a517.2bE62D  aElsgolts, L. 0aDifferential Equations and The Calculus of Variations  aMoscowbMir, Publishersc1970  a440  aMathematics  aPure Sciences  aCalculus  aDifferential equations  aVariations