Norman K. Denzin, Yvonna S. Lincoln, editors
Sage Publications, 2000
Buku Referensi
Strauss, Anselm L.
Cambrigde University Press, 1987
Buku Teks
Patton, Michael Quinn
Sage, 1990
Buku Teks
Ritzer, George
Nusa Media, 2012
Buku Teks
Hilt, Rinehart and Winston, 1967
Buku Teks