Saul, John Ralston, author
Penguin Books, 1997
Buku Teks
Resnikoff, H.L.
Holt, Rinehart and Winston, 1973
Buku Teks
Lipson, Leslie, author
Vakils, Feffer and Simons Private, 1964
Buku Teks
Ferguson, Wallace K., author
Sir Isaac Pitman & Sons, [date of publication not identified]
Buku Teks
Runciman, Steven
Meridian Books, 1959
Buku Teks