Peale, Norman Vincent, 1898-1993, author
Prentice-Hall, 1954
Buku Teks
Veronika Trimardhany, author
Fakultas Psikologi Universitas Indonesia, 2003
UI - Skripsi Membership
Davenport, Diana
Pan Books, 1979
Buku Teks
Titiek Triwidodo, author
Gramedia Widiasarana Indonesia, 2004
Buku Teks
Doi, Takeo
Kodansha International, Ltd., 1985
Buku Teks