Artikel Jurnal
edited by S. Pompe
Martinus Nijhoff, 1992
Buku Teks
Jacob, Herbert, 1933-, author
Yale University Press, 1996
Buku Teks
Smith, Christopher E.
Nelson-Hall Publishers, 1992
Buku Teks
edited by James Piscatori
Westview Press, 1987
Buku Teks