Creswell, John W., author
SAGE Publications, 2018
Buku Teks
Norman K. Denzin, Yvonna S. Lincoln, editors
Sage Publications, 2000
Buku Referensi
Strauss, Anselm L., author
Cambrigde University Press, 1987
Buku Teks
Patton, Michael Quinn, author
Sage, 1990
Buku Teks
Ritzer, George, author
Nusa Media, 2012
Buku Teks