Pile, John, author
Watson-Guptil, 1976
Buku Referensi
Harmon, Sharon Koomen, author
John Wiley & Sons, 2001
Buku Referensi
Harmon, Sharon Koomen, author
John Wiley & Sons, 2011
Buku Teks
Zevon, Susan, author
Rockport Publishers, 1996
Buku Teks
Westall, Christopher
Hongkong : Page One Publishing, 2002,
Buku Referensi