@article{1255989315, author = {Eck, David J.}, title = {Natural sheaves}, journal = {Illinois J. Math.}, volume = {31}, number = {2}, year = {1987}, pages = { 200-207}, language = {en}, url = {http://dml.mathdoc.fr/item/1255989315} }
Eck, David J. Natural sheaves. Illinois J. Math., Tome 31 (1987) no. 2, pp. 200-207. http://gdmltest.u-ga.fr/item/1255989315/