Harrison, W.E.C.
Oxford University Press, 1957
Buku Teks
Spencer, Robert A.
Oxford University Press, 1959
Buku Teks
Keegan, John
Gale Research, 1983
Buku Teks
Masters, Donald C.
Oxford University Press , 1959
Buku Teks
Keirstead, Burton Seely
Oxford University Press, 1956
Buku Teks