Soward, F.H., author
Oxford University Press, 1950
Buku Teks
Harrison, W.E.C., author
Oxford University Press, 1957
Buku Teks
Spencer, Robert A., author
Oxford University Press, 1959
Buku Teks
Keegan, John, author
Gale Research, 1983
Buku Teks
Masters, Donald C.
Oxford University Press , 1959
Buku Teks