by Howard W. Alexander... [et.al.]
W.A. Benjamin, 1968
Buku Teks SO
Makkink, H.J.
Nijgh and Van Ditmar, 1951
Buku Teks SO
Helling, Pam
[American Management Association, ], 1992
eBooks
Langan, John, 1942-
McGraw-Hill, 2013
Buku Teks SO
Harder, Paul O.
Allyn and Bacon, 1975
Buku Teks SO