Grbich, Carol
Allen and Unwin, 1999
Buku Teks
Kvale, Steinar
SAGE Publications, 1996
Buku Teks
Brinkmann, Svend
Sage Publications , 2015
Buku Teks
Punch, Keith F.
SAGE Publications, 1998
Buku Teks
edited by Christina Hughes
Open University Press, 2003
Buku Teks