Ott, Bill, author
[American Management Association;, ], 2009
eBooks
Page, Stephen J.
Royutledge, 1995
Buku Teks
Lazarsfeld, Paul F., author
Amo Press, 1971
Buku Teks
Page, Geoff, author
Angus & Robertson, 1988
Buku Teks
Wachlin, Steven, author
KITLV Press, 1994
Buku Referensi