Karl, Frederick R., author
Thames & Hudson, 1970
Buku Teks
Frank, Frederick S., author
Garland Publishing, 1987
Buku Referensi
edited by Arthur Waldhorn, Olga S. Weber, Arthur Zeiger
R.R. Bowker, 1990
Buku Teks
Saricks, Joyce G., author
[American Management Association, ], 2009
eBooks
Peter Salim, author
Modern English Press , 1997
Buku Referensi