Holmes, Janet
Longman, 1993
Buku Teks
Penguin Books, 1974
Buku Teks
Wardhaugh, Ronald, author
Blackwell Publishers, 2002
Buku Teks
Wardhaugh, Ronald, author
Wiley-Blackwell, 2010
Buku Teks
Wardhaugh, Ronald, author
Blackwell Publishers, 2002
Buku Teks