Godfrev, Jana
Hodder and Stoughton , 1993
Buku Teks
Shan, Darren, author
Gramedia Pustaka Utama, 2002
Buku Teks
Bentzen, Mary M.
McGraw-Hill, 1974
Buku Teks
Universitas Indonesia, 2005
UI - Skripsi (Membership)
Universitas Indonesia, 2004
UI - Skripsi (Membership)