Blanchard, Robert E., author
John Wiley & Sons, 1975
Buku Teks
Feld, barry c., author
Thomson/West, 2009
Buku Teks
Asean Law Association of the Philippines. Inc, 1982
Majalah, Jurnal, Buletin
Steel, E.W. (Ernest William)
McGraw-Hill, 1960
Buku Teks
edited by James Swarbrick
CRC Press, Taylor & Francis Group, 2013
Buku Referensi