Clarke, Philip
David & Charles, 1973
Buku Teks
Pradhira Adikara
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 2017
UI - Skripsi Membership
Braverman, Jerome D.
Van Nostrand Reinhold, 1984
Buku Teks
edited by Giorgio Calcagnini and Ilario Favaretto
Springer, 2012
eBooks
Block, Zenas
Harvard Business School Press, 1993
Buku Teks SO