Aldridge, Susan
Cambridge University Press, 1996
Buku Teks
Rao, K. Ranganatha, author
Prentice Hall of India, 1980
Buku Teks
Campbell, Mary K., author
Brooks/Cole Cengage Learning, 2008
Buku Teks
Garrett, R. (Reginald), author
Saunders College, 1995
Buku Teks
Mathews, Christopher K., author
Addison-Wesley, 2000
Buku Teks