Rice, Pranee Liamputtong, author
Oxford University Press, 1999
Buku Teks
Grbich, Carol, author
Allen and Unwin, 1999
Buku Teks
edited by Ann Bowling, Shah Ebrahim
Open University Press, 2007
Buku Teks
Jacobsen, Kathyn, author
Jones & Bartlett Learning, 2012
Buku Teks
Baumgartner, Ted A., author
McGraw Hil , 2013
Buku Teks