Klose, Paul S., author
Dow Jones-Irwin, 1989
Buku Referensi
Day, A. Colin, author
Oxford University Press , 1990
Buku Teks
Simone, Luisa, author
Microsoft Press, 1992
Buku Teks
Edited by Eleanor Harman
University of Toronto, 1961
Buku Teks
Murray, Katherine, 1961- author
Que, 1992
Buku Teks