compiled by E.G. Withycombe
Clarendom Press, 1950
Buku Referensi
Plamen Makariev
The Council for Research in Values and Philosophy, 2001
Buku Teks
Niebuhr, Reinhold, author
Nisbet & Co., 1946
Buku Teks
edited by, John T. McNeill; translated and indexed by, Ford Lewis Battles
The Westminster Press, [date of publication not identified]
Buku Teks
Sawyer, Deborah F, author
Routledge, 1996
Buku Teks