@article{IM_1968__5_141924,
     author = {F. OORT and D. MUMFORD},
     title = {Deformations and {Liftings} of {Finite,} {Commutative} {Group} {Schemes.}},
     journal = {Inventiones mathematicae},
     pages = {317--334},
     publisher = {mathdoc},
     volume = {5},
     year = {1968},
     zbl = {0179.49901},
     url = {http://geodesic.mathdoc.fr/item/IM_1968__5_141924/}
}