Artikel Jurnal
Ivanova, Vera Fedorovna, author
Leningradskogo Universiteta, 1962
Buku Referensi
Barkovskiy, Matvey Mikhaylovich, author
Vyshejshaya Shkola, 1974
Buku Referensi
Gorbachevich, Kirill Sergeyevich, author
Prosvesshenie, 1971
Buku Referensi
Vul`fson, R.Ye., author
Prosveshhenie, 1967
Buku Referensi