Richard G. Seymour, editor
Edward Elgar, 2012
Buku Teks
Thyer, Bruce A.
London : Sage Publications, 2001,
Buku Referensi
editor, Bruce A. Thyer
Sage Publications, 2001
Buku Referensi
Abbas Tashakkori, Charles Teddlie
SAGE Publications, 2010
Buku Teks
edited by Malcolm Williams and W. Paul Vogt
Sage, 2011
Buku Teks