@article{VMUMM_1983_2_a4,
     author = {S. N. Fedin},
     title = {Proper classes corresponding to the functors $n\cdot\operatorname{Ext}$},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {22--24},
     year = {1983},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1983_2_a4/}
}