@article{MZM_1971_9_3_a1,
     author = {F. I. Kagan},
     title = {Lifts as isomorphisms of graded algebras},
     journal = {Matemati\v{c}eskie zametki},
     pages = {239--247},
     publisher = {mathdoc},
     volume = {9},
     number = {3},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1971_9_3_a1/}
}