Saul, John Ralston
Penguin Books, 1997
Buku Teks SO
Lazarus, Neil, 1953-
Cambridge University Press, 2011
eBooks
Gagliardi, Robert M.
John Wiley & Sons, 1976
Buku Teks
Samuel Kalos Sampelan
Fakultas Ilmu Pengetahuan Budaya Universitas Indonesia, 2022
UI - Tugas Akhir
Keiser, Gerd E.
McGraw-Hill, 1991
Buku Teks