Baker, Sunny, author
Prentice-Hall, 1992
Buku Referensi
McCarthy, Richard C., author
[American Library association;American Library association, American Library association], 2007
eBooks
Walliman, Nicholas, author
Sage Publications Ltd , 2001
Buku Teks
Richman, Larry, author
[American Management Association, ], 2002
eBooks
Drago, Carl, author
Blackwell Publishing, 2007
Buku Referensi