Ganderton, Lucinda, author
Page One, 2002
Buku Referensi
Meredith, Carol, author
Rockport Publishers, 2000
Buku Referensi
Rocknow, H.K., author
Stuttman, 1954
Buku Teks
Lowell, Christopher, author
Discovery Books, 2000
Buku Teks
Livingston, Kathryn
Rockport Publishers, 1999
Buku Teks