England, Alan
Macmillan Education, 1990
Buku Teks
Read, Alan
Routledge, 1993
Buku Teks
edited by Phyllis Hartnoll
Oxford University Press, 1951
Buku Referensi
Aston, Elaine, author
Routledge, 1991
Buku Teks
edited by John Parker
Pitman, 1952
Buku Referensi