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Dover, 1955
Buku Teks
Simbolon, Aladin Edivollo
Fakultas Psikologi Universitas Indonesia, 1989
UI - Skripsi (Membership)
Kaniasari
1997
UI - Skripsi (Membership)
Bertyna Y.M.P.
Universitas Indonesia, 2002
UI - Skripsi (Membership)
Juneman Abraham
Department of Psychology Universitas Bina Nusantara, 2014
Artikel Jurnal