@article{IVM_1972_11_a12,
     author = {S. R. Firshtein},
     title = {Normal solvability of integro-differential equations},
     journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
     pages = {90--97},
     year = {1972},
     number = {11},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/IVM_1972_11_a12/}
}