@article{GDZPPN002375125, title = {A Note on the Extremal Surfaces in the Calculus of Variations}, journal = {Mathematische Zeitschrift}, volume = {38}, year = {1934}, pages = {465-467}, zbl = {0008.36103}, url = {http://dml.mathdoc.fr/item/GDZPPN002375125} }
Haviland, E. K. A Note on the Extremal Surfaces in the Calculus of Variations. Mathematische Zeitschrift, Tome 38 (1934) pp. 465-467. http://gdmltest.u-ga.fr/item/GDZPPN002375125/