Toffler, Alvin, author
Pantja Simpati, 1989
Buku Teks
Stavrianos, L.S.
W.H. Freeman and Company, 1976
Buku Teks
Krutch, Joseph Wood, author
Random House, 1959
Buku Teks
Willener, Alfred
Pantheon Books, 1970
Buku Teks
Drucker, Peter F. (Peter Ferdinand), 1909-2005, author
Harper & Brothers, 1959
Buku Teks