Babkina, A.M.
Russkij Yazyk, 1975
Buku Referensi
Shtevnfeldt, E.
Progress, [date of publication not identified]
Buku Referensi
Akademija nauk SSSR
Nauka, 1975
Buku Referensi
Myuller, V.K.
Sovetskaja-Entsiklopedija, 1969
Buku Referensi
Ozhegov, S.I.
Russkij Yazyk, 1981
Buku Referensi