Baring-Gould, Sabine, author
Longman, 1906
Buku Teks
general editor, H.R. Loyn
Thames and Hudson, 1991
Buku Referensi
Halliday, Fred, author
Cambridge University Press, 2005
Buku Teks
Hoyt, Robert S., author
Harcourt, Brace & World, 1966
Buku Teks
Mosse, Fernand, author
The Johns Hopkins Press, 1952
Buku Teks