@article{SEMR_2020_17_a12,
     author = {S. V. Sudoplatov},
     title = {Approximations of theories},
     journal = {Sibirskie \`elektronnye matemati\v{c}eskie izvesti\^a},
     pages = {715--725},
     publisher = {mathdoc},
     volume = {17},
     year = {2020},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/SEMR_2020_17_a12/}
}