Kaiser, Edward John
Buku Teks
Chapin, F. Stuart (Francis Stuart), 1916-
University of Illinois Press, 1979
Buku Teks
Silver, Edward A.
John Wiley & Sons, 1998
Buku Teks
Curtin, Daniel J.
Solano Press Books, 1993
Buku Teks
Stuart, Darwin G.
Praeger, 1976
Buku Teks