Bell, Judith, author
McGraw-Hill Education, 2014
Buku Teks
Bell, Judith, author
Open University Press, 1993
Buku Teks
Walliman, Nicholas, author
Sage Publications Ltd , 2001
Buku Teks
Coghlan, David, author
Sage, 2001
Buku Teks
Briney, Kristin, author
Pelagic Publishing, 2015
Buku Teks