Stead, Christina
Angus and Robertson Publishers, 1987
Buku Teks
Marshall, Jock
Sun Books, 1968
Buku Teks
Kent, Ernest W.
Mc-Graw-Hill Publications Co., 1981
Buku Teks
Finch, Janet, author
George Allen and Unwin, 1983
Buku Teks
Blau, Joseph L., author
Prentice-Hall, 1965
Buku Teks