Coppock, Vicki, author
SAGE, 2010
Buku Teks
Rhodhes, Margaret L., author
Routledge and Kegan Paul, 1986
Buku Teks
Oliver, Michael, 1945
Macmillan Press, 1996
Buku Teks
Simons, Ronald L., author
Macmillan, 1985
Buku Teks
Grinnell, Richard M., author
Oxford University Press, 2018
Buku Teks