Quinn, K. A. S., author
Metamind, 2015
Buku Teks
Rangkuti, Freddy, author
Gramedia Pustaka Utama, 2000
Buku Teks
Bradley, Alan, author
Sigma Press, 1993
Buku Teks
Neale, J. E., author
Alden Press, 1950
Buku Referensi
by Lytton Strachey
Chatto and Windus, 1951
Buku Teks