edited by Joanna Household
Webb & Bower, 1983
Buku Referensi
Keir, David Lindsay, author
Adam and Charles Black, 1961
Buku Teks
Lenin, Vladimir I., author
Foreign Languages Publishing House , [date of publication not identified]
Buku Teks
Childs, David
Methuen, 1979
Buku Teks
Evans, David, author
Routledge, 1997
Buku Teks