Rockport publishers, Inc., 2008
Buku Referensi
Simmons, Christopher, 1973-, author
Rockport, 2006
Buku Referensi
Harvey, Alan R., author
Oxford University Press, 2016
eBooks
Kalbe, 2006
Buku Teks
Sutton, Tina, author
Page One Publishing, 2008
Buku Referensi