Phoenix Publishing Limited, 2011
Buku Referensi
Gluck, Peter L.
Rockport Publishers, 1997
Buku Teks
Crosbie, Michael J.
Rockport Publishers, 1998
Buku Teks
Crosbie, Michael J.
Rockport Pub., 1998
Buku Teks
Browne, Enrique
Rockport Publishers, 1997
Buku Teks