Dupre, Flint O, author
Harper & Row, 1967
Buku Teks
Lenin, Vladimir I., author
Foreign Languages Publishing House , [date of publication not identified]
Buku Teks
Laski, Harold J., author
Manchester University Press, 1951
Buku Teks
Srivastava, G.P., author
Chand , 1965
Buku Teks
Monck, Bosworth
Phoenix House Limited, 1952
Buku Teks