Robertson, John M., author
Watts & Co, 1931
Buku Teks
Leroux, Jean-Marie, author
Notre Dame, 1963
Buku Teks
Niebuhr, Reinhold, author
Nisbet & Co., 1946
Buku Teks
Blondel, Maurice., 1861-1949
Press University de France, 1950
Buku Teks
Seeley, John Robert, author
JM Dent & Sons, 1932
Buku Teks