Kassirsky, I., author
Peace Publisher, [Date of publication not identified]
Buku Referensi
Kassirsky, I., author
Mir Publisher, 1969
Buku Teks
Camp, L. Sprague de, author
Holt, Rinehart & Winston, 1952
Buku Teks
Brodrick, Alan Houghton
Oxford University Press, 1942
Buku Teks
Senior, Michael, author
Longman, 1979
Buku Teks