Heers, Jacques
North-Holland Publishing, 1977
Buku Teks SO
Erlande-Brandenburg, Alain
Thames and Hudson, [Date of publication not identified]
Buku Teks
Baring-Gould, Sabine
Longman, 1906
Buku Teks
general editor, H.R. Loyn
Thames and Hudson, 1991
Buku Referensi
Salzman, L.F.
Oxford University Press, 1955
Buku Teks SO