Lusin, Natala
Baron's Education, 1992
Buku Referensi
Smirnitsky, A.I., author
Higher School Publishing House, 1975
Buku Teks
Timberlake, Alan, author
Cambridge University Press, 2004
Buku Teks
Hinkel, Eli
Baron's, 1994
Buku Referensi
Maltzoff, Nicholas, author
Ellinois Passport Book, 1994
Buku Teks