Balmer, Randall, author
Baylor University Press, 2016
Buku Teks
edited by Jess Stein
Dell Publishing, 1962
Buku Referensi
Krooss, Herman Edward, 1912-1975, author
Prentice-Hall, 1972
Buku Teks
Patrick, John
Macmillan Publishing Company, 1984
Buku Teks
Quint, Howard H
Dorsey Press, 1968
Buku Teks