Lasnik, Howard
Blackwell, 1999
Buku Teks SO
Aurora Cuito
HBI and Loft Publications, 2001
Buku Teks SO
Radford, Andrew
Cambridge University Press, 2003
eBooks
Radford, Andrew
Cambridge University Press, 1997
eBooks
Meredith, Carol
Rockport Publishers, 2000
Buku Referensi