Feather, John
Library Association Publishing, 1998
Buku Teks SO
Feather, John
Facet Publishing, 2004
Buku Teks SO
edited by Susan Hornby, Zoe Clarke
Facet, 2004
Buku Teks SO
Martin, William J.
Brookfield, Vt., USA : Gower,, 1995.
Buku Teks SO
Webster, Frank
Routledge, 1995
Buku Teks SO