McGraw-Hill , 1998
Buku Teks
Browning, Paul
Reality Press Ltd, 2009
Buku Teks
Newell, Michael W.
American Management Association, 2005
eBooks
Lammle, Todd
Wiley , 2011
Buku Teks
Yuli Kurnia Ningsih
Fakultas Teknik Universitas Indonesia, 1992
UI - Skripsi Membership