@article{GDZPPN002090333, title = {A Flatness Criterion in Grothendieck Categories.}, journal = {Inventiones mathematicae}, volume = {20}, year = {1973}, pages = {331-336}, zbl = {0257.18020}, url = {http://dml.mathdoc.fr/item/GDZPPN002090333} }
Ulmer, Friedrich. A Flatness Criterion in Grothendieck Categories.. Inventiones mathematicae, Tome 20 (1973) pp. 331-336. http://gdmltest.u-ga.fr/item/GDZPPN002090333/