Latourette, Kenneth Scott, author
Penguin Books, 1954
Buku Teks
Janse, Olov R.T., author
St-Catherine Press, 1958
Buku Teks
Ritonga, Pra Ulpa Treeda, author
Fakultas Ilmu Sosial dan Ilmu Politik Universitas Indonesia, 2011
UI - Skripsi (Open)
Bucknall, Kevin B., author
Allen &Unwin, 1989
Buku Teks
Schwartz, Harry, author
Atheneum, 1966
Buku Teks