Scales, Peter, 1949-
Open University Press, 2013
Buku Teks
Galloway, David
Longman, 1987
Buku Teks
Cobb, Jeff
[American Management Association, ], 2013
eBooks
Evans, Norman, 1923-
Routledge, 2001
Buku Teks
Scott, Ronaldo Mota David
Elsevier, 2014
eBooks