Mayall, James
Cambridge University Press, 1990
Buku Teks
Costa, Horacio La de
Solidaridad Publishing House, 1965
Buku Teks SO
Deutsch, Karl Wolfgang, 1912-1992
MIT Press, 1972
Buku Teks SO
University League for Social Reform; edited by Peter Russell
McGraw-Hill, 1966
Buku Teks
Eun Kyung Kim
OMNES, 2018
Artikel Jurnal