Sutherland, Zena, author
Longman, 1997
Buku Teks
Tschudin, Verena, author
Butterworth-Heinemann , 2007
Buku Teks
Marshall, Richard E., author
Saunders, 1982
Buku Teks
Click, Phyllis, author
Wadsworth/Clengage Learning , 2012
Buku Teks
Bowden, Peta, 1946-, author
Routledge, 1997
Buku Teks