@article{MZ_1934__38_168508,
     author = {E. K. Haviland},
     title = {A {Note} on the {Extremal} {Surfaces} in the {Calculus} of {Variations}},
     journal = {Mathematische Zeitschrift},
     pages = {465--467},
     publisher = {mathdoc},
     volume = {38},
     year = {1934},
     zbl = {0008.36103},
     url = {http://geodesic.mathdoc.fr/item/MZ_1934__38_168508/}
}