Gavin Andrews, Mark Creamer, Rocco Crino, Caroline Hunt, Lisa Lampe, Andrew Page
Cambridge University Press, 2003
Buku Referensi
edited by Cecilia A. Essau, Franz Petermann
Routledge, 2001
Buku Teks SO
edited by Cecilia A. Essau and Franz Petermann
Taylor & Francis, 2001
Buku Teks
Cecilia A Essau, Franz Petermann, editor
Taylor & Francis Inc, 2001
Buku Teks SO
edited by Robert T. Woods
John Wiley & Sons, 1999
Buku Teks SO