Schiff, Frank W.
New York, N.Y. Committee for Economic Development 1980.,
Buku Teks
Kuhn, James W., author
Harcourt, Brace & World, 1968
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Artikel Jurnal
Steiner, George A. (George Albert), 1912-, author
Random House, 1972
Buku Teks
Sarnoff, David, author
McGraw-Hill, 1968
Buku Teks