@article{AM2_1971__6_136203,
     author = {S.P. LIPSHITZ},
     title = {A {Solution} of the {'Converse} {Canonical} {Problem'} for {Multiple} {Integrals} in the {Calculus} of {Variations}},
     journal = {Aequationes mathematicae},
     pages = {288--305},
     publisher = {mathdoc},
     volume = {6},
     year = {1971},
     zbl = {0223.49017},
     url = {http://geodesic.mathdoc.fr/item/AM2_1971__6_136203/}
}