John Hartley [and others]
Rinehart and Winston, 1962
Buku Teks
Fairbairn, Gavin, author
McGraw-Hill, 2012
Buku Teks
Smith, Brenda D., author
Longman, 2000
Buku Teks
McWhorter, Kathleen T., author
Pearson/Longman, 2007
Buku Teks
Wood, Nancy V., author
McGraw-Hill, 1991
Buku Teks