Soltau, Roger H.
Longmans, Green , 1960
Buku Teks
Littlejohn, Ronnie L., author
I.B. Tauris, 2011
Buku Teks
Harris, Phil, author
Weidenfeld and Nicolson, 1993
Buku Teks
Hames, Joanne Banker, author
Prentice-Hall, 1998
Buku Teks
edited by Harry Daniels
Routledge, 2005
Buku Teks