@article{1077490636, author = {Ader, Olin B.}, title = {An affine invariant of convex regions}, journal = {Duke Math. J.}, volume = {4}, number = {1}, year = {1938}, pages = { 291-299}, language = {en}, url = {http://dml.mathdoc.fr/item/1077490636} }
Ader, Olin B. An affine invariant of convex regions. Duke Math. J., Tome 4 (1938) no. 1, pp. 291-299. http://gdmltest.u-ga.fr/item/1077490636/