@article{1077472369, author = {Young, L. C.}, title = {An expression connected with the area of a surface $z=F(x,y)$}, journal = {Duke Math. J.}, volume = {11}, number = {1}, year = {1944}, pages = { 43-57}, language = {en}, url = {http://dml.mathdoc.fr/item/1077472369} }
Young, L. C. An expression connected with the area of a surface $z=F(x,y)$. Duke Math. J., Tome 11 (1944) no. 1, pp. 43-57. http://gdmltest.u-ga.fr/item/1077472369/