Routledge, 1997
Buku Teks
Easton, David, author
Prentice-Hall, 1965
Buku Teks
Somit, Albert
Dryden Press, 1974
Buku Teks
Sudijono Sastroatmodjo, author
IKIP Semarang, 1995
Buku Teks
Mahathir bin Mohamad, 1925-, author
Pelanduk Publications, 1986
Buku Teks