Bradford, Richard, 1957-
Routledge, 2001
Buku Teks
Heffernan, James A.W.
W.W. Norton & Company, 1986
Buku Teks
edited by W.A. Paton
Ronald Press, 1955
Buku Teks
Prentice-Hall, 1991
Buku Referensi
Frederick S. Merritt and Jonathan T. Ricketts, editor
McGraw-Hill, Inc, 1994
Buku Referensi