Finkelstein, Leo
McGraw-Hill , 2000
Buku Teks
general editor, Philip Rubens
Henry Holt and Company, 1992
Buku Referensi
Trzyna, Thomas N.
Wadsworth, 1987
Buku Teks
Lindsay, David
Longman, 1995
Buku Teks
Van Duyn, Julia
John Wiley & Sons, 1982
Buku Referensi