Brightman, Edgar Sheffield
Holt, Rinehart and Winston, 1961
Buku Teks SO
Randall, John Herman
Barnes & Noble, 1957
Buku Teks SO
Maritain, Jacques, 1882-1973
Rowman & Littlefield Publishers, 2005
Buku Teks SO
Hales, Steven D.
Wiley Balckwell, 2013
Buku Teks SO
Graham, Gordon
Routledge, 1997
Buku Teks SO