@article{DAN_1968_179_3_a1,
     author = {D. L. Berman},
     title = {Certain linear polynomial operations in a complex region},
     journal = {Doklady Akademii Nauk},
     pages = {507--510},
     year = {1968},
     volume = {179},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1968_179_3_a1/}
}