Levy, Leonard W.
Harper, 1963
Buku Teks
Beer, Lawrence Ward
Kodansha International, 1984
Buku Teks
Steinby, Torsten
Government, 1971
Buku Teks
edited by Herman Wasserman
Routledge, 2013
Buku Teks
Nibras Nada Nailufar
2016
UI - Makalah dan Kertas Kerja