Marshall, Catherine, author
Sage, 1999
Buku Teks
Silverman, David, author
Buku Teks
Walle, Alf H., author
Quorum Books, 2001
Buku Teks
edited by Norman K. Denzin, Yvonna S. Lincoln
Sage, 2011
Buku Referensi
Norman K. Denzin, Yvonna S. Lincoln, editor
Sage , 2011
Buku Teks