Sydney Hicks,Smith & Sons Pty LTD 1973,
Buku Referensi
Wilson, Jerry S.
American Management Association;, 2008
eBooks
WordPerfect Corporation, 1992
Buku Referensi
Parker, Elizabeth
Librarry Association , 1999
Buku Teks
Hackos, JoAnn T.
John Wiley & Sons, 1994
Buku Referensi