Hicks, John R., author
The Clarendon Press, 1952
Buku Teks
Hicks, John R., author
Oxford University Press, 1975
Buku Teks
Slavin, Stephen, author
Richard D. Irwin, 1991
Buku Teks
Morgan, Theodore, author
Prentice-Hall, 1950
Buku Teks
Cairncross, Alec, author
Butterworth, 1960
Buku Teks