Weisinger, Hendrie, author
American Management Association, 2000
eBooks
Peale, Norman Vincent, 1898-1993, author
Prentice-Hall, 1954
Buku Teks
Biswas-Diener, Robert, author
Wiley, 2010
Buku Teks
Daniels, Aubrey C., author
Mc-Graw-Hill, 2000
Buku Teks
Abifa Arif, author
Fakultas Psikologi Universitas Indonesia, 2012
UI - Skripsi (Open)