Bossing, Nelson L.
Laidlaw Brothers, 1956
Buku Teks
edited by Thom Brooks
Blackwell, 2008
Buku Teks SO
Hall, J. Oliver
America Book Company, 1958
Buku Teks
Hukum dan Pembangunan, XXVIII (4) Juli Agustus 1998: 252-261, 1998
Artikel Jurnal
edited by Jody Heymann, Adele Cassola
Cambridge University Press, 2012
Buku Teks