Bamborough, J.B., author
Longman, 1959
Buku Teks
Kerr, Robert S.
A Macfadden Capitol Hill Book, 1963
Buku Teks
Choate, Mark S., author
Wiley Publishing, Inc., 2008
Buku Teks
Terrell Ward Bynum, Simon Rogerson, editors
Blackwell Publishing, 2010
Buku Teks
Kelly, Lucie Young
London MacMillan 1975 , 1975
Buku Teks