@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/