McGraw-Hill, 1971
Buku Teks
Sjoberg, Gideon
Harper & Row Publishers, 1968
Buku Teks
Gomm, Roger, author
Palgrave McMillan, 2004
Buku Teks
edited by George Mckenzie, Jackie Powell, Robin Usher
The Falmer Press, 1997
Buku Teks
edited by Else Oyen
Sage, 1992
Buku Teks