@article{GDZPPN002220075, title = {A Variational Proof of the Gauss-Bonnet Formula.}, journal = {Manuscripta mathematica}, volume = {22}, year = {1977}, pages = {245-254}, zbl = {0351.53035}, url = {http://dml.mathdoc.fr/item/GDZPPN002220075} }
Armsen, Moritz. A Variational Proof of the Gauss-Bonnet Formula.. Manuscripta mathematica, Tome 22 (1977) pp. 245-254. http://gdmltest.u-ga.fr/item/GDZPPN002220075/