Hall, Borden
Harper & Brothers, 1955
Buku Teks
Tanner, Ogden., author
Time-Life Books, 1978.
Buku Referensi
Church, Thomas D.
McGraw-Hill, 1985
Buku Teks
edited by Nigel Dunnett, James Hitcmough
Taylor and Francis, 2003
Buku Teks
Crockett, James Underwood
Time-life books, 1975
Buku Teks