Hughes, Edward, author
John Wiley & Sons, 1987
Buku Teks
Hughes, Edward, author
Longman, 1991
Buku Teks
Hughes, Edward, author
Pearson Education, 2002
Buku Teks
Bartkiw, Walter L.
McGraw-Hill Ryerson, 1986
Buku Teks
Stout, Melville B.
Prentice Hall of India, 1981
Buku Teks