@article{IM_1971__13_142084,
     author = {L. Gruson and M Raynaud},
     title = {Crit\`eres de platitude et de projectivit\'e {Techniques} de },
     journal = {Inventiones mathematicae},
     pages = {1--89},
     publisher = {mathdoc},
     volume = {13},
     year = {1971},
     zbl = {0227.14010},
     url = {http://geodesic.mathdoc.fr/item/IM_1971__13_142084/}
}