Glenne, Michael
Roy Publishers, [date of publication not identified]
Buku Teks
Fry, Peter Somerset
Routledge , 2001
Buku Teks
Webb, Keith
Molendinar Press, 1977
Buku Teks
Burnett, John
National Museums of Scotland, 1995
Buku Teks
Tait, Alan A.
Edinburgh University Press, 1980
Buku Teks