Weston, Paul B.
Prentoce-Hall, 1981
Buku Teks
Blanchard, Robert E.
John Wiley & Sons, 1975
Buku Teks
Feld, barry c.
Thomson/West, 2009
Buku Teks
Asean Law Association of the Philippines. Inc, 1982
Majalah, Jurnal, Buletin
Adams, Thomas F.
Prentice-Hall, 1980
Buku Teks