Hoogendoorn, J.
UI-Press, 1989.
Buku Teks
Cohen, William A.
American Management Association, 2008
eBooks
Deverell, C.S.
London, Gee & Co
Buku Teks
Sri Purwaningsih
2017
UI - Skripsi (Membership)
Stroup, Jim
American Management Association, 2008
eBooks