White, Jon
Business Book Limited, 1991
Buku Referensi
Chan, Janis Fisher
[American Management Association;, ], 2007
eBooks
Lexis Nexis, 2009
Buku Teks SO
Rashelle S. Karp, editor
[American Library association, American Library association], 2002
eBooks
Greene, Gardiner G.
McGraw-Hill, 1975
Buku Teks