Walton, Richard E
Addison-Wesley, 1987
Buku Teks
edited by David B. Lipsky, Ariel C. Avgar, J. Ryan Lamare
Emerald, 2016
eBooks
Likert, Rensis
McGraw-Hill, 1976
Buku Teks
Pfeiffer, 2003
Buku Teks
Peters, Jan Hendrik, author
Trisakti University, 1999
Buku Teks