Osborne, Milton E., author
Allen & Unwin, 2016
Buku Teks
edited by Deborah Cherry
Blackwell, 2005
Buku Teks
Williams, Lea E.
Oxford University Press, Inc, 1976
Buku Teks
Progressio, 1972
Buku Teks
edited by Nicholas Tarling
Cambridge University Press, 1994
Buku Teks