East, Roger
Profiles of people in power: the world's goverment leaders
Routledge, 2006
 Buku Referensi
Nixon, Richard
Leaders
Warner Books, 1982
 Buku Teks SO
Community leaders of the world / Published The American Bibliographical Institute
The American Bibliographical Institute, 1986
 Buku Referensi
Schuman, Frederick L.
International politics: the Western state system and the world community
McGraw-Hill, 1958
 Buku Teks SO
Murphy, Robert F.
Robert H. Lowie
Columbia University Press, 1972
 Buku Teks SO