Crowell, Thomas Lee, author
McGraw-Hill, 1987
Buku Referensi
Fowler, H. W. (Henry Watson), 1858-1933
Oxford University Press, 1983
Buku Referensi
New, W.H., author
Copp Clark Pitman, 1986
Buku Teks
Xiandai, Ying, author
Foreign Languages Teaching and Research Press, 2001
Buku Referensi
Weis, Erich, author
National Textbook Company, 1993
Buku Referensi