Reynolds, Amanda, author
Open universtity press , 2000
Buku Teks
edited by Saul Feldman
Charles C. Thomas, 1980
Buku Teks
edited by Allan McNaught
Chapman and Hall , 1991
Buku Teks
Goodwin, Nick, author
McGraw-Hill Open Univ. Press, 2006
Buku Teks
edited by Charles B. Inlander, Alan M. Rees
Oryx, 1991
Buku Teks