Rossman, Gretchen B., author
Sage, 2003
Buku Teks
Punch, Keith F., author
SAGE Publications, 1998
Buku Teks
edited by Christina Hughes
Open University Press, 2003
Buku Teks
Bailey, Susan, author
Jones & Bartlett Learning, 2013
Buku Teks
Jacobsen, Kathryn H., author
Jones & Bartlett Learning, 2017
Buku Teks