Davis, Diane E., author
Cambridge University Press, 2004
Buku Teks
Routledge, 1996
Buku Teks
Halliday, Jon, author
Penguin Books, 1974
Buku Teks
edited by Eduardo P. Archetti
MacMillan Education, 1987
Buku Teks
Szulc, Tad, author
Atheneum, 1966
Buku Teks