Nobbs, Jack
Macmillan Education, Ltd., 1989
Buku Teks
Finsterbusch, Kurt, author
McGraw-Hill, 2006
Buku Teks
Kurt Finsterbusch, editor
McGraw-Hill, 2007
Buku Teks
Farley, John E., author
Prentice-Hall, 1992
Buku Teks
Fulcher, James, author
Oxford University Press, 2007
Buku Teks