Rothman, Kenneth J.
Lippincott Williams / Wilkins, 2008
Buku Teks SO
Edwards, Anne
Longman, 1996
Buku Teks SO
Walliman, Nicholas
Sage Publications Ltd , 2001
Buku Teks SO
Yu-Kang Tu, editor
[, Springer], 2012
eBooks
editors, Yu-Kang Tu, Darren C. Greenwood
Springer , 2012
Buku Teks SO