Messier, Ric
Syngress, 2014
Buku Teks SO
Gerring, John
Cambridge University Press, 2017
Buku Teks SO
Paul C. Adams, Julie Cupples, Kevin Glynn, André Jansson and Shaun Moores, authors
Routledge, 2017
Buku Teks SO
editor-in-chief, Donald H. Johnsto
Academic press, 2003
Buku Referensi
edited by Athina A. Lazakidou
Springer, 2012
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