Chemie, B.G.
Springer-Verlag, 1990
Buku Teks
McCray, Arthur W.
Prentice-Hall, 1975
Buku Teks
Publishing Science Group, Inc., 1973
Buku Teks
Tolle, Lauren Woodward
[Springer, ], 2012
eBooks
ASTD Research Study
American Management Association, 2009
eBooks