Yaukey, David
Princenton University Press, 1961
Buku Teks SO
Office of The Coordinating Minister for Social Welfare and Poverty Alleviation, 1998
Buku Referensi
Muhyiddin
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 2007
UI - Tesis Membership
Edmonds, Richard Louis
Routledge , 1994
Buku Teks
Harbison, Frederick Harris
McGraw-Hill, 1965
Buku Teks SO