Sayers, W.C. Berwick, author
Deutsch, 1967
Buku Teks
Marcella, Rita, author
Gower ; Jaico Publishing House,
Buku Referensi
Chan, Lois Mai, author
McGraw-Hill, 1994
Buku Teks
Batley, Sue, author
Chandos, 2005
Buku Teks
Taylor, Arlene G., author
Libraries Unlimited, 1992
Buku Teks