@article{ZVMMF_1976_16_4_a2,
     author = {V. P. Il'in},
     title = {Some estimates for conjugate gradient methods},
     journal = {\v{Z}urnal vy\v{c}islitelʹnoj matematiki i matemati\v{c}eskoj fiziki},
     pages = {847--855},
     publisher = {mathdoc},
     volume = {16},
     number = {4},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZVMMF_1976_16_4_a2/}
}