Routledge, 2006
eBooks
Swaaningen, Rene van, author
Sage, 1997
Buku Teks
Vold, George B. (George Bryan), 1896-1967, author
Oxford University Press, 1979
Buku Teks
edited by Mary Bosworth and Carolyn Hoyle
Oxford University Press, 2013
Buku Teks
Petherick, Wayne A., author
Elsevier, 2010
Buku Teks