Betty, John G. (John Galtress), 1922-, author
McGraw-Hill, 1993
Buku Teks
Casey, Francis, author
Macmillan, 1985
Buku Referensi
Hart, Andrew, author
Routledge, 1997
Buku Referensi
Thorn, Eric A., author
Jay Books, 1989
Buku Referensi
Ewles, Linda, author
Scutari Press, 1995
Buku Referensi