Edwards, David
Sage Publication, 2004, 2004
Buku Teks
edited by Diane Elizabeth Waller and Andrea Gilroy
Open University Press, 1992
Buku Referensi
edited Judith Aron Rubin
Bunner-routletge, 2001
Buku Teks
Simon, Rita M.
Routledge, 1997
Buku Teks
Van Nostrand Reinhold, 1986
Buku Teks