Harberts, Kurt, author
Frederick A. Preager, 1963,
Buku Teks
Buchman, Dian Dincin, author
NTC Publishing Group,U.S., 2002
Buku Teks
Stevenson, Burton, author
New York, Harper & Brothers
Buku Referensi
Berman, Alan
FrancesLincoln limited, 1997
Buku Teks
edited by L. Edward Purcell
Prentice-Hall, 1991
Buku Referensi