Reardon. Bernard M.G.
Longman, 1981
Buku Teks
Gorman, G.E., author
Grenwood Press, 1986
Buku Referensi
David F. Ford, Rachel Muers, editor
Blackwell Publishing, 2008
Buku Teks
Sarah Citra Cornelia, author
Fakultas Ilmu Pengetahuan dan Budaya Universitas Indonesia, 2018
UI - Skripsi Membership
Niebuhr, Reinhold, author
Charles Scribner's Sons, 1955
Buku Teks