Lutz, William D.
Cambridge University Press, 1994
Buku Referensi
Herkimer, Herbert
W.M. PennPublishing Corp., 1952
Buku Teks
edited by Geoffrey Parker
Cambridge University Press, 1995
Buku Referensi
Porter, Roy, 1946-2002
Cambridge University Press, 1996
Buku Referensi
edited by Michael Hoskin
Cambridge University Press, 1997
Buku Referensi