Hayes, Carlton J. H.
Macmillan, 1955
Buku Teks
Gunther, John, 1901-1970, author
Harper & Brothers, 1961
Buku Teks
Gunther, John, 1901-1970, author
Harper & Brother, 1962
Buku Teks
Europa Publications Limited, 1970
Buku Referensi
Roberts, Geoffrey
Manchester University Press, 1984
Buku Teks