by Andrew West [and others]
Fourmat Publishing, 1992
Buku Teks
Weston, Martin
Oxford, 1991
Buku Teks
Weston, Martin
Berg Publishers, 1993
Buku Teks
Gooch, R.K. (Robert Kent), 1893-1982
Appleton-Century, 1935
Buku Teks
Fisher, Howard D.
Cavendish Publishing Limited, 1999
Buku Teks