Comfort, Jeremy, author
Oxford University Press, 1994
Buku Teks
Laws, Valerie
Buku Teks
Tippens, Paul E., author
McGraw-Hill, 1983
Buku Teks
Washington, Allyn J., author
Pearson - Prentice Hall, 2009
Buku Teks
Clynes, A.J., author
International Development Program of Australian Universities, 1985
Buku Teks