@article{DAN_1987_294_2_a2,
     author = {R. G. Nigmatullin},
     title = {Two classes of proofs of lower bounds on complexity},
     journal = {Doklady Akademii Nauk},
     pages = {272--275},
     year = {1987},
     volume = {294},
     number = {2},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1987_294_2_a2/}
}