Walton, Donald, author
McGraw-Hill , 1989
Buku Teks
Tingley, Judith C., author
American Management Association;;, 1996
eBooks
Mortensen, Kurt W., author
American Management Association, 2008
eBooks
De Mare, George
John Wiley , 1979
Buku Teks
Fakultas Ilmu Sosial dan Ilmu Politik Universitas Indonesia, 2014
UI - Tugas Akhir