Rowlands, Penelope, author
Chronicle Books, 2000
Buku Referensi
Cerver, Francisco Asensio, author
Konemann, 2000
Buku Teks
Prati, Lacroze Miguens, author
Rockport Pub., 1997
Buku Teks
Hollister, C. Warren, author
John Wiley & Sons, 1968
Buku Teks
Fennell, John
Longman, 1983
Buku Teks